From Eonline:

Ali is definitely still a part of Heroes. Niki Sanders, not so much, but Ali will stick around and conjure up a whole new personality we haven't yet seen before for season three: Tracy Strauss.

Kinda lame and repetitive.
Gotta say I'm not really looking forward to Niki's story this season,
but you never know - it could be interesting.

i was looking forward to seeing jessica again ripping people in half. but we dont know what sort of personality tracy strauss will have. hopefully she will be even more deadly

I agree, seeing Ali playing the killer type Jessica was would definetly be fun. She was so cool back then!
But on the other hand, Flying Man! is right, it would be a bit lame(or let's just say uncreative) because it'd be just repeating the first season. Plus it would be a tough time for sweetie Micah.
I hope the authors have come up with a totally new type of character to make it interesting.

yea really the only reason i could see for a "new" personality was removing her from Micah. But they easily could have used Gina for that. I just had remembered there was a lot of talk of if Ali was a regular or not so figured i'd post it on that aspect.