I only watched the show a couple of times & I liked it.  But what nobody has mentioned (or that I have seen so far--I have not read the entire thread and did miss a page or two at most) is that Charlie is not off the show because of his personal life.  He is off the show because he violated the terms of his contract with the production company when he publicly blasted his supervisors, producers, and the people who sign his paycheck.  NOBODY in the business is allowed to do that, and Charlie thought he was special and that those terms of his contract did not apply to him.
Sheen's off the show because of a contract violation.  The producers and powers-that-be at CBS even put up with his rants for a while, but then he crossed a line when he started making public comments to/about Chuck Lorre.  He shot himself in the foot on that one.
I think he will get help--I certainly hope so!  Charlie Sheen's been a favorite of mine since her was a young kid in Red Dawn.  I liked Two And A Half Men the few times I did see it, but I am going to reserve judgment for how I feel about Kutcher stepping into the role.  He's been good in some of the things he's been in, not-so-good in others.  This might be just the niche he's been looking for, and if the writers do their job well, and Kutcher steps up to the plate, this can work. 
I'm remaining open-minded and hopeful that Charlie gets it together and continues to have a successful career after this--and publicly apologizes to the producers of the show.  Who knows?  Maybe he'll get his job back.  By then the kid will be grown, Kutcher will be a mainstay on the show, and it'll be "Four Men".  LOL.