If you could make one balance change to every class on P99:

[Wakanda]

Wizards get clarity-line of spells.

Magicians get root-line of spells.

Necromancers and Monks are both given innate natural regeneration. Give these passives some cool names like "touch of the grave" and "inner spirit." This doesn't stack with Iksar regen.

Enchanters are nerfed to make charm less reliable, forcing Enchanters into a support role.

Rogues can now use poison making to create an item called "crimson veil." When consumed this item gives the Rogue regeneration for 60 minutes. Would help Rogues solo since IMHO they are the worst class at solo'ing.

Shadow Knights get lich line of spells (I'm sorry but pulling/tanking as an SK is frustrating because I never have mana). I also think Harm Touch should be resisted less, and should work as a life-tap instead of flat damage.

Warriors gain out-of-combat HP regeneration (meditate?).

Shaman has torpor nerfed to it's original state that made it a much more niche and gimmicky spell.

Bards seem balanced already? Like maybe their songs could affect other groups or pets. Or maybe more races could play as bards.

Clerics and Paladins are given Bane DMG: Undead.

Druids can now teleport to all of the old broken druid rings (Rathe Mountain, OOT, Gfay, Permafrost etc.). The nerf to torpor is an indirect buff to Druids.

Rangers can now tame random animals from across norrath and summon them as pets. The class will probably still suck, but this would feel cool and thematic.