interesting take on that-I'll provide the opposite viewpoint.
I didn't necessarily see her try to copy his ability and fail at it either.
Have they shown her doing her eye thing at every single thing going on? no.
With that in mind it's hard for me to believe she can't do those supernatural things yet until she has actually tried and failed at them.
So, I still wonder if it's possible with her.
I'd be willing to put money on her not being able to mimic actual powers. The only thing that makes me think your theory might be right is something I read way back in EW from the creators that said there would be a finite number of powers among the Heroes, but that those powers might initially manifest themselves in different ways. If that is true, then she, Peter, and Sylar may all have the same power. Likewise, Parkman, the illusionist chick, and Parkman's dad all may have the same power of reading/messing with people's minds. For now, I'm sticking with the guess that she's just able to copy non-powered skills.