Evil Bad Guy: Traps Wizard and Cleric behind Wall of Force to deal with Fighter and Rogue.
Wizard: Grabs Cleric buddy, teleports past wall.
Cleric: Flame Strike
Rogue: Sneak Attack
Fighter: Charge
Evil Bad Guy: Ah, I'm dead.
Not too good of a plan; quite frankly, I'd rather hit my enemies with real magic that can consume their souls or turn them to tapeworms instead of making them waste one round.
A D-Anchor on the wizard generally works well, but if used solely for that purpose that's two rounds you're wasting to trap him. One of my problems in my 3e game was that the characters would always use the Bracelet of Friends to pop out of Walls of Force.
The problem with Wall of Fire and Wall of Ice is that the damage is a joke. 2d6+level? Who can't take that kind of damage? Sissy elven wizards? If a whopping 27 points of damage, from a 15th level caster, is threatening then you probably shouldn't be taking on this guy in the first place. It's a question of marginal utility; sure, damaging the group with a Wall of Fire might be useful, but is it as useful as other 4th level spells cast in its place?