Force is kind of a nebulous thing in D&D. When it's a wall or shield it's invisibile, when it's fired at someone it's suddenlty colorful (can't go letting wizards fire invisible missiles at people, now can we?). A cage or wall of force can't be dispelled even though one would think it's a sustained magical effect, but it can be disintegrated as easily as a slab of stone.
Yeah, force is odd, but I can kinda understand the reasoning here. A wall or forcecage is a constructed "object" like a wall of ice or a wall of iron - just because it's temporary doesn't make it any "real". Personally, I would rule that you couldn't dispel any other wall effect either (course, most of them are instantaneous anyway) simply because it would subvert the purpose of the wall to do otherwise. A wall of ice or thorns is easy enough to get through without spells - hack it down or melt/burn it with fire spells. You can get around a
wall of force with
dimension door or one of the new teleportation spells.
I always wondered why 3e did away with multi-schooled spells in the first place. Some spells just scream more than one school to me.
Because it simplifies the system. It cuts down on the number of times the spell appears in the spell lists (which saves space), and if it's in one school, there's no arguments about whether or not a specialist can take it. Yeah, I know, the new spells have that clause, but... I'm another one that thinks the idea of dual-school spells is absurd.
Let's look at
Kelgore's grave mist as an example. The spell "conjures" a thin mist that doesn't hamper vision; all living creatures in the cloud become fatigued and take 1d6 cold damage/rd. There is no save to avoid either effect, but if you have SR and you make the check, you can avoid the fatigue. And this is a L2 spell. IMO, it would have been fine as a straight necromancy spell with a Fort save; if you fail the save, you avoid the fatigue.
Or
Kelgore's fire bolt. This is a really wonky spell - you "conjure" a rock and sheathe it in fire (the Evocation part), then throw it at the target. It deals 1d6 fire damage/level (max 5d6) and allows a Ref save for half, but if you fail to overcome the SR, it still deals 1d6 fire damage "from the heat and force of the conjured orb's impact". WTF? Why can't this be a straight Evocation spell where you pick a rock up off the ground, make it burst into flame, and throw it at someone?
I think 4e is already here. It's right under our noses. New stat block formats, swift and immediate actions, the polymorph subschool...
My DM said the same thing when I told him about the new stuff that was featured in the previews - that they're just testing a whole bunch of new stuff to see what works and what doesn't, and the stuff that works (or at least, what players like, which is not necessarily the same thing) will go into the new edition. I have to hand it to them, though - this is pretty slick: they're combining playtesting and market analysis in fell swoop. By handing it off to the general populace, they can see if the new rules work in Joe Gamer's game, and they also see what we think of them. "Well, dual-school spells didn't really go over well, so they're out for 4E, but swift and immediate actions are a hit - they're in."
But maybe I'm just reading too much into this.