My view this is as Jake has been growing up the show has had to change a bit, and I dunno if it was for the better or worse, but the show isn't what it used to be, if that is Jake's fault or if the show has just been on for too long I can't say.
I kinda like Jake's character, so I would like for them to keep him on, but right now the big question is will there even be a 8th season as news that Charlie Sheen doesn't want to do the show anymore has surfaced.
But the idea of Charlie having some kid somewhere and having him move in there could actually be great, thats a great idea