Lol. My caster parties abuse the hell out of multi-classed casters. My normal setup usually looks like:
Fighter/Cleric
Fighter/Mage
Mage/Theif
Mage/Cleric
Mage
X
X can be anything, a bard, a Fighter/Mage/Thief, anything at all.
Here's what you get. You get 2 clerics, 4! mages (one pure, 3 half, but all the best damage spells are low level, and by TOB you'll all be casting high level spells) A thief to handle your locks and other junk, 2 fighters that are both very capable in combat (Cleric Fighter buffed with a ton of the self cast buffs you get can be a very potent class combo, and the Fighter/Mage is no scrub with Mirror Image + Stoneskin... by the time he's hit, the enemies are dead.)
The only difficulty is ranged, you only get 1! longbow user and one shortbow/light crossbow user. That's where X comes into play.
You can sling and dart the hell out of your enemies though.
But the real power of the party is the 4 mages. 4 fireballs at the start of any encounter tends to turn the tide very quickly. Unless they're immune to fire, which means you better find another trick.
I like these parties because I like nukers. I just don't want to end up with the boringness of the solo sorceror.
All mages isn't tough if you know how to use them. And I certainly know how to use them
