There's no ignorance whatsoever in your post, and it's an issue that many people have different opinions on, both in Italy and abroad.
One school of thought goes with what you suggested, that Ancelotti has been there too long and that a new coach is needed to inject new ideas. The players may be getting complacent under his management e.t.c.
Personally, I don't subscribe to that. You look at England, and you see people like Ferguson and Wenger who have enjoyed success and have both been at their respective clubs for some time. Fergie has had some poor seasons, in particular from 2003 to 2007 when they didn't win a league title. There were calls for him to be sacked and yet he was trusted and has built a new side.
This is why I want Carletto to stay. We're a family club, so to speak. A lot of the back room staff are former players, and they all know the club and its ethos inside out. Besides, who would we get if he did leave? Who is there that is actually good enough?
I also don't believe the current situation is entirely his fault. I'm not convinced all of the players that arrived in the summer were players he wanted. There's also the age of the squad - which has been allowed to creep up year upon year without being addressed. It has left us in the situation we are in now, where 90% of players are now getting too old and wholesale surgery needs performing to the squad. One area he does need to look at, and where he is partly responsible for the mess, is the system and players he's picking. Playing 4-3-2-1 will only work if we play an attacking midfielder in the 3. Flamini, Pirlo, Ambrosini are all defensive players. Asking one of them to attack is rubbish because they won't be as good as a proper attacking midfielder. As it is, we have Inzaghi, then Kaka & Ronaldinho behind him, then a gap, then the midfield three. Very easy to defend against.
Our best system is a 4-3-1-2, with Kaka in behind. He refuses to use this until we're actually losing a match though.