Because it's nonsense. I can't wait to see this in action. Get 5 perks that increase how much you can carry but despite your obvious enormous strength and constitution your health/damage/speed do not grow with it. No, attributes are the best way to represent some things and they killed them.
Attributes were totally superfluous because they never should have raised on level. They should have raised on SKILL level. As I swing around my huge warhammer, my strength should raise as well. Well, once you take that step to have them level at the same time, doesn't that effectively make strength = weapon skill (or whatever skill you had that was governed by strength). Then what's the difference between having your perks emulate as IF you HAD high strength. For instance, once you reached a certain point in Two handed weapons, you might get a blunt weapon perk that lets you strike an enemy hard enough to throw them back several feet. That is a REFLECTION of the strength that your character WOULD have as a result of the all the hard work raising that skill.
Its the difference between raise skill -> raise strength -> get perk based on strength that knocks enemies back OR raise skill -> get perk. You're just cutting out the middle step, its just that strength is now IMPLIED by ones skill level. Having a 100 in two handed weapons heavily implies that I am a heaping ball of muscles, because it would follow logically, and would be no different as if I did ACTUALLY have 100 strength.