I don't remember any particularly interesting magic in Morrowind, but the spell customization was good. I created a spell to summon all parts of the Daedric armor at once – it saved a lot of space in my inventory.
While I agree that warriors scale better, thanks to the base weapon damage from blacksmithing and damage buffs from enchanting, I wouldn't call mages weak. I easily completed the game as a pure mage, who actively used only Destruction magic, and I didn't notice any problems in battles with enemies – all sorts of Alduins went down in a couple of seconds. The only problem might be elemental resistance, if you decide to specialize in only one element. But even so, using mostly electricity, I had to switch to another type of damage only once – during the battle with Morokei.
Well, yes, the game is generally easy, and if you don't come up with special role-playing restrictions for yourself, it's hard to mess up your build.