In all fairness you don't really judge an actress by their roles but the quality of their roles, and I've seen much worse quality in other actors around her age bracket. Lindsey Lohan is obviously older but her entire career has been one hollywood flop after another.
I think K. Stewart gets called on for the more serious roles because thats simply what shes mastered so far. Even though Angelina Jolie defined herself in Girl Interupted it wasn't till years later she really developed as a competent actor, just that now shes too big a sellout to action/maneating roles. Are they more exciting than K. Stew? I guess.. but would I rather watch K. Stew over one of Hollywoods more competent actors? Umm yeh.
I'm saying not to define an actor by their role but I just defined Angelina, what I meant was don't define a young actor by their roles. Some people are natural born talents from birth, like Leonardo Dicaprio, imo hes ALWAYS been an excellent actor. Other people take some time to full develop (K. Stew/Angelina), while other actors regress imo, like Robert Deniro. And in terms of K. Stew not being attractive, I just have to assume you have a congenital vision problem since birth and haven't figured it out yet. K. Stew has a "natural hot" look to her, she doesn't wear make up outside of photoshoots (while tootsie seems to have makeup on in every photo I've seen) so I think like Ocean said different people define attraction differently.
When I see girls with dark black eye liner and stripes in their hair it makes me think "look at me look how hot I am the whole world needs to know" while girls like K. Stew are rather humble, and secure in their natural look. And I think thats part of the reason I find her so attractive. Shes a chameleon who can match her background, and a diamond in the rough all at the same time. Versatility for w/e reason is superattractive.