My point is the producers wrote the show with little to no leeway to allow Charlie a way to return in a logical way. If the situation had been that Charlie decided to leave the show to star in movies again, the producers would've laid the groundwork for a possible return. Something more on the line of Charlie went missing or had died under mysterious circumstances. That was not the case.
What happened was.....
Charlie was fired from the show.
Charlie publicly insulted his boss.
Charlie told the world the show was nothing without him.
Charlie said they would hire him back.
The producer put a message at the end of each show basically saying how much Charlie sucked.
The producer would not and still won't take Charlie's calls.
It is my guess that the producer has taken the position that Charlie will never be a part of Two and half men as long as he is in charge.
I think the funeral scene was symbolic for the way the producer felt. What better way to show Charlie just how much he cares than to have him run over by a train, everyone wanting to spit on his corpse and then have him cremated with no chance to return.
That episode was way more about burning personal bridges than plotting a clever return for Charlie. It was the ultimate GFY
That's my prediction, archived here for later reference when the whole thing is said and done.