Attributes are a layer of numbers between the things that actually matter in the game . . .
That's actually part of the reason they were so useful. While I think we'll be fine without certain attributes such as intelligence, there is still the issue of things like carry weight. There are two ways to address these through perks and skills alone:
1. A convoluted formula that uses certain skill levels to make a rough summation of how much your character should be able to carry as assumed by their skills. Something like, say, 100 - 200( 1 / [skills added] ) + ( skills added ) / 6. It allows for just as much diversity in players and NPCs' encumbrance as the old attributes allowed, except difficult to understand, having been founded upon an intangible formula. http://uesp.net/wiki/Morrowind:Combat#Attacks
2. Alternatively, we use perks! After all, perks can do everything, right? Possibly, and I myself think the perks system could be pretty well-developed, but have fun trying to explain something such as encumbrance being in a weapon skill tree. "By swinging your sword so often, your shoulders and back muscles are stronger." Oh, but worst of all, this isn't a nice gradual progression like the previous games! I'd rather not go from a weapon skill of, say, 47 to 48 and then magically gain an additional 20 units of max encumbrance.
Honestly, I'd rather have some neat numbers adding up to my character's carry weight in a way I can understand and plan out.