People say that Alicia left LG to not get distracted by Will, while others say she left to be with Will. But im not sure which one to believe. Anyone help me out?

"[...] exec producer Robert King insists that when Alicia aligned herself with Cary she was essentially severing ties with Will. 'She’s leaving Lockhart/Gardner because she needs to create distance between herself and Will' he explains. 'She knows the kiss has opened a door and the only way to close it is to get away from him.'"

I got the quote but I realized the website where I found it has already been a part of an answer. =)

The assumption that she left because she wants to get closer to him, well.. this is exactly the opposite of what RK said. And (although being a Willicia fan myself, I think that) mostly fans who only watch the show because of Willicia, want to hear that this move is supposed to bring them back together.

Well, for me it was open to interpretation, but the producers had said it was to not get distracted by Will.

link

I think that now that Peter's made the governor, and will not be in Chicago anymore, it would allow more screen space for Will and Alicia's character to play out.
This most probably would involve many more explosive moments between them seeing that we know how much Will would be pissed with Alicia leaving and views it sort of a betrayal to him both professionally and personally.
However, the sexual tension is there and even more now because unlike the Mock Trial in the episode 'Red Team, Blue Team' , these two would be fighting over actual cases.

But I do believe that this will be the first time that Will would be genuinely pissed with Alicia and so, it most probably would take most of the upcoming season for them to get back together.
We have to take into account here that of the two, only Will realizes his love for Alicia; this I believe is another reason why I feel that the writers are keeping these two apart because they want to give time to Alicia to realize that this isn't just lust which she feels for Will.

I would love it if the writers could give us a flashback episode of Georgetown days so that the fans can know what actually transpired between Will & Alicia there, and how she ended up marrying Peter. Will left Tammy's sister to be with Alicia in college and it would be wonderful to know how everything went down.
It would be even more awesome to have Will and Alicia go back to Georgetown in Wash.DC to solve a case. And then have all the flashbacks and maybe this could be a great way for Will to become less pissed with Alicia.