I haven't been impressed with Wizards so far, but I just got Paradigm Shift and that certainly seems like it has potential. My Enchantress has been on the team for giggles than anything, but with the AoE-stuff unlocking she's a bit more useful.
I love gishes but I also haven't been impressed with Rune-Fencer/Valkyrie. Seems like a poor man's Ninja for the most part.
EDIT: I'm expecting my Enchantress to become quite a bit better once I unlock the +3 range staff though. Because she can't use Baldur Mace, she skips the +2 weapon meaning you get a huge increase when the +3 staff becomes available.
Mages are really toned down/nerfed in this version. You'd have to have perspective about how good they used to be vs how they are in this version. The reason why mages are shit, is because finishers use MP in this game, which sort of invalidates mages as an offensive tool. In the PS1 version, mages got an area 2 AOE with the basic spell (once their INT level increased), and then learned a summon spell which could multi-hit one target for big damage (usually a oneshot), so they were pretty powerful. In this version they're not even 1/4 as good. Not only that, but mages are super squishy, and the enemy AI tends to go out of their way to isolate them. Rune Fencers are 90% as good as mages with spells, and can also use a heal, and don't get easily picked off by enemy archers, and have MP regen for finishers. Rune fencers also learn a 0MP cost activation skill in the late 20s, early 30s, so that level 3 missile spell or heal ends up being free. I gave my rune fencers spears. At 30 skill they learn a ranged AOE finisher that hits in a + that does big damage for 60mp cost. The sorta offense I wish I had on a mage, but they never actually get. Even if mages get better options in post game in this version, I say too little too late.