i'd probably change WHM's spell effects back to something elemental/conjury based, since holy holy and more holy is just bland.

for other's changes i'd probably steal a lot of pages from Papachin's modding work for several classes--things like adding mudra pings/particles and elemental visual effects for the NIN gcd attacks (and his clientside damage segmentation/display thing is super fuckin rad? like legit i'm shocked that's not a thing in the game already with as seemingly easily as he added it)

not that i or anyone else would ever use mods, especially not ones that fix problems like making every head item in the game viera and hrothgar compatible (with variable ear clipping/nonclipping options per user preference)
definitely not, because that would make them a dirty crime boy