Most of these have been said before in other posts, but a few of these I haven’t seen talked about. Also, for the sake of being helpful I’m going to try and limit anything I suggest to what could realistically be implemented (though I’m not a game developer so I may be off on what is easy and not).
Targeting could be made more powerful by letting players tweak the number. This could have a selection like: x targets within x range instead of assuming single target. This could make good group buffs or hastily add in AOE functionality. Maybe even options like “All” for Auras. (In the future this could be pushed to using simple targeting shapes like instead of “targets” you may be able to select shapes (cone, square, circle) and then have the range denoted the origin of the shape from the caster)
For cooldowns, a passive option, or maybe for the game’s sake, a “toggle”, for constant effects. These Constants could turn costs into costs per second. (These could possibly be used to add more abilities into the game. Passives/toggles should be easier to track than having the AI select abilities and track cooldowns so what if every second level gives a Passive ability slot in addition to a normal ability slot, that way classes could be made more unique faster.)
Another idea are different activations for cooldowns - something like # of kills, or amount of health lost.
For casting time, I’d love to see a Channel option, which would be the ability starts immediately, but the player must continue to cast for the effects to apply (basically any time based effect would become as long as the player decided to channel. Maybe the duration could apply only after the channel ends? So a Channel stun of 1 second would last as long as the casts the ability + 1 second)
What if there was a “Self Effect” section? This would be useful for adding in side effects of an ability. This could simply copy all of the Effects (except Siphons), but apply only to the caster - always. That way an ability could deal a lot of damage but weaken the user afterward and other fun combinations. This breaks the current “Self” target at the moment, but it should be easy to make clear how to make Self only, beneficial abilities.
The current effects are pretty powerful, but there’s some strong ones that are missing, like increasing/decreasing damage of the target. Dodge chance/miss chance would be neat - they would function somewhat different from “Protect” and “Weaken” in that debuffs aren’t affected by protect and weaken, but could be negated by miss or dodge. Critical chance/reducing critical chance as well. Monster manipulation effects like Fear or Charm may be interesting (fear making the monster actively run away, Charm making them fight for you for a short time) though I worry they might be too close, functionally, to stuns. Similar to the “Protect” and “Weaken” what if there was “Resist” and “Expose” for percent reductions/increases to times/effects of debuffs.
(Side note: I’ve noticed that there are no “random” elements in the game atm. Is this something that is too difficult to track?)
An option to manage how/if specific abilities scale with level would be nice. A low level protect ability might want to scale a lot to slightly to not at all (how the game does it now). Damage abilities are less of an issue, but it would be nice to allow the core attack abilities to scale better but not be overpowered at low levels.
That’s about all I can think of at the moment. Hopefully these are relatively easy to implement (excuse my ignorance if they’re not). People always suggest stuff like Summoning, but I always feel like that would take a lot of doing to make work. The idea is that these might be more possible in the shorter term, and I hope that they are helpful in that way.