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

[Dundrige]

I would give Paladins increased melee DPS against undead. I like what Luclin did with the undead proc buffs.

Rangers get the same charm animal abilities as Druid.

Rogue poisons are much more powerful and useful.

Warrior's taunt have increased hate generated over other classes.

Clerics get badass nukes against undead. Think wizard-level.

Wizards have more interesting utility spells. Their evac when things get dicey is almost instant and brings the group to the zoneline. They get area of effect stuns, roots, fears, and snares that don't generate a ton of aggro. They get the Rune line equivalent to enchanters. Critical nukes occur more often on Wizards.

And like Gandalf, combat wizards can be a thing. Still as squishy, and the weapons available might not be as great, and not as much DPS as a pure melee, but think Paladin or Shadowknight level DPS with equivalent weapons.

Magician's summoned armor / weapons / items scale with level and actually get really good and worth using by level 60, even on well-equipped characters, but the spells require special items that might or might not be worth it to get for a temporary item.

Magicians, alongside their powerful damage shield spells, can also imbue other's weapons with various elemental damage procs... earth gives a root proc, air gives a stun, fire & water give straight damage, etc.

Monster summoning is a more powerful alternative to summoning pets for magicians. The pets you summon have the same abilities as the NPC they are copied from.

Magicians & Wizard's elemental based nukes do more than just damage. Fire-based nukes are a DoT afterwards, ice-based nukes mez mobs for a tick or two, but straight magic does the most damage right away.

Shadowknights get a special irresistible (except against named) ability to charm undead equivalent to their level for a few minutes in battle.

Shadowknights get a self-only damage shield line.