For those who haven't seen the aforementioned scene yet, http://www.youtube.com/watch?v=nCEjeTb1rrs. Just to get the feeling, try to you recall everything that happened in the latest season of your favourite TV show. Now, imagine that in next episode the creators would nullify the whole picture with such a stupid move, basically telling straight to your face that nothing was real in the past season. Matter of fact, it never happened. Therefore just forget about cliffhangers, character progressions, new actors and let's back to square one. Yes, it was that incredible lame.
Back to the OP's question, it's really unlikely. IIRC the relationship between Chuck Lorre and Charlie Sheen was never ideal to begin with, but it really hit rock bottom in the past few years. Since then they're doing okay on their own, what would be the incentive for reunion? Maybe Sheen would be in it because the decreasing popularity of Anger Management, but Lorre is the major factor in this situation. Problem is that he constantly has 3 - 4 show on rotation in TV, plus Two and Half Men is probably end in a season or two anyway. Asthon Kutcher was one of, if not the best choice to replace Sheen (even if he's definitely weaker in the role than his predecessor); add to the mix his top-notch salary and you'll get another reason why it's unlikely to bring things back like they were.