I think if someone wants to build an ubermage, they should be able to build an ubermage.
My pure mages in Oblivion wear no armor and if they carry a weapon, it's a dagger that used only for blocking. They specialize in one or maybe two schools of magic and pump all their increases into intelligence, willpower, agility and speed. They end up the classic physically weak and low HP pure mages, just because I prefer to play them that way.
It sounds as if the new system might limit players to a similar build, so that won't be that much of an issue for me, but with the fact that it's innately limiting, if it doesn't allow the creation of the sort of mage I'd prefer to build, then I'm stuck with whatever the finite range of perks might provide. And anyone who wishes to play another type of mage - and particularly the uber kind - is also stuck with whatever the finite range of perks might provide.
I can't help but think that those players who believe that to be a good thing are living in some pretty serious denial....
Wait, I don't get this.
So there should be a way to great an uber-character, one that is good at everything, but you're still worried about the number of possible archetypes? If it is possible to create an uber-character it would decrease the number of meaningful archetypes to that one, because if you can become the best at everything with one character why would you want less.
This was the thing in Fable. There were many possible character builds but guess what kind of character did everybody played at the end? The muscle giant, with the arcane power of Elminster who's also a master thief, the rest of the builts were just for show, and people who want to go against the popular trends.
If you can create a character that can do basically everything, you don't need to create another character ever, because you've already did everything that new character could, except maybe if you're bored or just want to challenge yourself.
And I really don't know how Morrowind/Oblivion added much more archetypes anyway...