we can dual-wield spells, or have a spell in one hand and a weapon in the other... even go at it gandalf-style dual-wielding a staff and a weapon!
not only that, we can COMBINE spells if dual-wielding them, and use them in several different ways... like turning a fireball spell into a flamethrower, or placing a rune on the ground to create some kind of exploding spell!
skyrim's magic system is going to be alot of things, but one thing it isnt, is "simplified"... i also highly doubt they would get rid of all those spells that weaken the enemy... that would just be stupid.