Given from what I have seen so far...
These are possible:
2) The ability to edit the inital class "description" like Knight or Wizard.
4) The ability to completely remove all currently existing spellbooks and skill trees. I also want to rename the categories the skill trees are under.
7) Have skill trees that can go beyond 5 levels.
8) Change the EXP Curve.
9) The ability to create my own item stats/effects.
theoretically possible:
3) The ability to assign specific trees to a player based on that initial class description, but to also be able to assign generic trees that anyone could invest into (I assume this is default functionality, but I am asking anyway.)
unknown:
1) The ability to add another bar to the UI. I want to implement secondary resource mechanics for different classes, and I need to be able to indicate the value of these resources, preferably under health.
5) Extend the combat system to include a projectile system that would cause all projectiles to act as seperate entities with their own speed and move values. Basically I want to make all bows, projectile spells, and such be able to be dodge-able/interactable for a short period of time as they travel to their target.
6) The ability to edit the functionality of different stats, level up growth rates/rewards, etc. Preferably I would like the ability to completely remove the Strength/Dex/Con etc.
