+2 Voidbane Cannon
The two highest UR wheel values currently are 25. Can consider those tokens to not be the greatest things ever at purple, but I'm also sensitive to the idea of setting a new benchmark.
So, math. Yes, the math on this isn't simple if want to get at average damage. Losing a round of another attack with the Cannon is not just losing the damage wheel, it's also losing the missile damage bonus. Just like Boom Stick duds are not just zero on the wheel but zero in total. So, I did four rounds of mock combat with both missile damage bonus of 0 and missile damage bonus of 32. Why 32? It's a very solid damage bonus at purple and the higher the missile damage bonus the more effect losing the next round matters.
Note, I did this after some much simpler calculations. Not looking for perfect accuracy on every possible result, as the numbers change based on how many rounds combat goes, what missile damage bonus is, how often going to crit versus miss, and whatever I don't care to actually incorporate.
Btw, Boom Stick is not a good weapon. That it has more popularity than some better weapons should help point out that mechanically better isn't always more desirable. Boom Stick is dramatic. While humans crave power, they also crave stories, and more dramatic events are more memorable. It's actually a bit tricky finding great comps to Voidbane. I settled on Darkbane as my comp since it's current, even if the bonus damage against Undead/Were introduces another arbitrary assumption.
Where my calculations ended up. With a +32 missile damage bonus and assuming Darkbane bonus kicks in one third of the time over four rounds of combat (not relevant for Darkbane but relevant for Voidbane), Darkbane averages 41.7 damage per round and Voidbane 43.6. Multiply that by number of damage wheel slots (6) and Voidbane wheel is about 12 points higher. More numbers I'm sure folks won't believe in are that only about 39% of the top wheel result apply due to the losing a round effect of being stunned when using four rounds and +32 missile bonus.
Now, being Stunned is different than not being able to attack with this weapon. For instance, someone who expects combat to last three rounds whatever they do who doesn't want to lose a round could do other things for first two rounds, then cannon up. So, it's going to be impossible to put any definitive number on this token.
Anyway, being leery of going from 25 to 40 and viewing this as clearly better than Darkbane, I would reduce top value to 30 (minus 4 to impact by very fluffy math), reduce second value from 20 to 15 (cleaner -5 to wheel) as it's better aesthetics if second value isn't higher than half of top value, reduce the lowest value to 5, the second lowest to 6 (just in case rogue gets added to token to Assassinate proof it). Then, whether want to reduce the ten to a nine is getting deep into the weeds on how feel about the token.
Whether such changes balance the token against Darkbane is ... not terribly relevant since balance is not something this game strives for. Far more relevant is whether consumers will acquire the same number of Voidbanes as they would have with a lower damage wheel *plus* the feelings of consumers about how Voidbane compares to what they already invested in. Yes, that's a lot of guesswork, but, note, what they have invested in doesn't just mean another 2h UR weapon but how consumers feel about new tokens in general and whether they obsolete what they've invested in.
Blood Cult Mark
This is really powerful. Far more powerful than +2 Will save/Mystic Staff bonus or +1 Fort save/+5hp (generally, class dependent, of course). Reflex saves are the least important and the easiest to increase at higher levels of play. Not excited by being able to stack an even higher max STR in this game, but I guess +2 STR/-2 Reflex would better fit. Speaking of kilts later, look at how Kilt of Barrelbane has the biggest minuses, as it was recognized that STR mattered more than DEX or CON.
Charm of Coordination
Most of the dev process is just throwing out opinions rather than fixing typos or whatever. I know I'm not the only one, but I might as well be for all that this is going to matter. I do not like synergy tokens. When I play with regulars, fine, whatever, waste a slot on Awakened Synergy because numbers go bigger. It may seem trivial, but having to adjust a build to account for who may or may not be running something once a run begins because I don't know what other people's builds are is annoying. Having treasure change based on who does or doesn't have a particular TE up until everyone just CoWs is annoying.
While there are teamwork benefits to coordinating builds, there's also a loss of individual build identity. The CoAS slot could be something that's actually interesting rather than my assuming it will be in every one of my Epic builds outside of solo play.
Cosmic Armor
More comments are not more impactful comments, but I happen to be in a more expansive mood. This is too generic. It wastes design space to not make tokens more specific, like how so many tokens have become plus damage to ranged attacks rather than having tokens for missle and tokens for spells. +2 to an attribute out of torso is really, really good. Now, if it's deemed in theme to be generic, +1 for versatility would make some sense to me. I realize that's not sexy.
Earcuff of Murmurs
URs often didn't fit the theme for the year. I assume this is overengineered to introduce some drawback on more tokens to fit the year of the drawback as well as have more tokens that bury Will saves, which is likely going to backfire as something that gets ignored rather consistently is that tokens don't exist in a vacuum where the cumulative impact of multiple tokens exacerbates changes in the game as we have seen with things like damage output. The vastly cleaner, not overengineered, version of this token is drop all of the stuff about saves.
Guiding Gauntlets
As a side note, as it's always good for arguing to start with a side note, while it's outside of typical to switch between melee and missile or melee and spell at UR+, it's rather easy to switch between missile and spell for many a build. So, ranged damage bonuses are much more double dipping along the lines of druid and Focus than other polyvalent damage bonuses.
Given how long blasters have been using Blessed Tempest Gloves, I'm not going to cry over an UR that gives +4 spell damage at this point. That is a more reasonable token than how tokens keep becoming overly broad.
IS Amethyst Sphere
I'll chime in on liking the idea but not the execution. Design and development are two different things, even if designers often do development and developers often do design. Designers are supposed to come up with cool ideas, different stuff, expand the boundaries of games. Developers are to make sure new ideas actually work, which routinely means killing what sounds cool because it just isn't worth the squeeze. Now, maybe someone will come up with a mechanic worth the squeeze, but I have my doubts this token, as composed, will be a good addition to the game.
Mask of Gaunt Luck
One more shot. -5 HP is a huge deal when playing with commons, major deal when playing with uncommons, deal when playing with rare tokens, minor at UR+ level. New slot and immediately get +3 more to saves. Now, as much saves are exploding everywhere, that just means can replace some other slot with more damage output. If this slot is supposed to be strong in the saves, well, okay, but it just seems early to have such a big gap between rare/blue and UR in terms of desirability of effect.
Natasha's Nightcap
Slotless tokens should do very little and should often be dependent upon consumables. So, I don't have a problem with this token in terms of what it does. While others may not use blue potions, I've used a lot to even getting to the point of running out. I just don't see a reason to keep adding more slotless tokens. Look at real world builds at high end play. They have absurd amounts of tokens in them. More slots is part of it, more slot expansion is part of it, more slotless is another part of it. Yes, we can choose to play 15 token builds or whatever, by we I, of course, mean me since Pelor forbid people not fill every slot. It's just more scrolling through deckbuilders.
Necklace of Baubles
Charm Bracelets, once upon a time, was an interesting token. It had competition, even if it was routinely BiS. Does this game believe in limiting builds through slots? Every time it introduces another slot expander, it undermines what the game originally played like, which was 3rd level dudes with chainmail, a longsword, and a potion.
Of course, it's not so much the UR that I have disdain for. Charm Necklace already exists. It's that slot expander paths just equal more slots for nothing but more $$. Can say there's a decision between class neck legendaries and more slot legendaries, but, at least, the class legendaries weren't more generic goodstuff tokens and reinforced some identity, even if they are largely overpowered.
Plague Cult Kilt
It makes sense to have an UR legs item. Does it make sense to just keep adding more damage to slots? While the odd token that increases 2h attacks of all types is "ooh, different", it's become not different anymore; yes, it broadens the token's appeal, but what has been increasingly lost is that not every token should be appealing to everybody for multiple reasons including how it's easier to trade when someone doesn't want everything. Yes, not everyone cares about 2h damage, but it's on the spectrum of too broad along with the other tokens mentioned above. I'm also not sanguine on the thematics of this. Breeches would be somewhat better, but that's not my primary thematic problem with it.
Spirit Pet Owl
The first spirit pet was too many spirit pets in the game. The rules around spirit pets are a mess. The lack of implementation with VTD is the biggest problem with them. At least red dragon was unique to try to add some "fun" to the game. In general, alchemical attack forms are overly complicated in the game already. Rather than just keep adding spirit pets and trying kludgy patches, may want to just rethink what role spirit pets are supposed to have in the game.
Tobin's Cosmic Ring
It's inelegant to have the paladin ability be an "or". Now, for a different comment, I'm not enthused by how much Sacred keeps getting added to the game. Sacred is messy. It may be on theme here, but themes are easy to change. Could be on theme for the year to be psychic damage, which is also kind of messy. As damage types like acid are less messy mechanically, should try to control use of different damage types more.