I would love to see safeholds with two variables:
1 - which character class is assigned to the safehold
2 - what kind of safehold it is
For instance, if you assign your safehold to the elf wizard, a certain suite of things may become enabled for you. Perhaps your safehold only requires 20 points to transmute enchanter's munition and oil of enchantment, while the general wizard would see those benefits on alchemist's ink & parchments (etc).
When selecting your type of safehold, you could declare it as production, martial, education, or arts. Production safeholds might generate pets, darkwood planks, a small amount of GP when you send in transmute materials, or something similar. Martial safeholds provide a 1/game runestone-like effect where a retainer does "a thing" in combat. Education, similar to martial but for puzzles. Arts, grants an opportunity to engage with a larger True Dungeon story as the year progresses.
Ensuring that these benefits when used in-game are mild is key, I think. New players (me!) can see that investment is rewarded, but may feel overwhelmed with both options and powerscale (slotless things, ioun stones, charms, beads, runestones, and so on). Seeing safeholds as something to which a TD character "retires" into between adventures rather than brings with them into the adventure would be pretty sweet!
I loved the idea of getting a keep, monastery, wizard's tower, and so on in my early D&D games. They became difficult to manage simply because they are inherently mechanical, which ultimately took the focus away from my character and placed that focus on my rewards. It's a fine line to walk, that's for sure.