To me, Skyrim's going to have roughly
as much customization as the previous games: it's just that it'll be a more concrete sort.
In Morrowind and Oblivion, as the OP described, much of what made your character personal stemmed from the way you designed them
outside of the context of the actual gameplay. I could make a class that was identical to a premade one, but give it some comical name like "Pack Mule" and then create an entire backstory (for my own purposes) about how they were renowned back in their home town for their carrying strength. I could also make spells and give them unusual effects or names: perhaps I swore to create fatigue-draining spells and then beat all of my enemies to death with my fists. Or maybe it was a signature move for each of my spells to heal the enemy and yet poison them at the same time
for whatever stupid reason. Lots of people may not really think about it, but I think we take foregranted just how much our own little touches affected the game.
In Skyrim, I feel as if Bethesda's throwing away some of this oldschool customization-through-imagination and are instead just trying to have the options right there and accessible from within the game itself. I'd be able to give my character scars and decals from the getgo, instead of compensating with something odd like always wearing a glove over my left hand to hide an imaginary one. We will now be able to ultimately determine our character's specialization through actually
playing and focusing on certain skills, instead of being limited by classes.
But I do think it's an unfair exchange. I still feel as if being able to cast each spell in multiple ways isn't really more diversity, it's just like turning them into FPS weapons that are too adaptable for too many situations. There better be some major limitations to how often you can, say, place flame traps. Higher magicka cost, short duration, less damage, whatever. But who knows? Bethesda has a tendency to pleasantly surprise me. :shrug: