No, I do not think Carlo should be fired. Firing Carlo, and hiring someone like Jose Mourinho would be like hiring a world class chef to cook a meal with old, stale, brazilian cuisine. If the ingredients aren't all that good the product will always suck.
Carletto has not done anything to impress this season, and he has held fast with lineups that have not worked but I think firing him now would cause way more harm than good. He needs to be able to right this ship before the decision made, granted his time is waning. He does deserve a chance though.
Who could replace Carlo? Mourinho? Cappello? Lippi? Well quite frankly I have no idea, there is always a chance that Milan will promote from within, such as Tassotti but thats a question I almost afraid to contemplate.
Finally, I would like to hear the tifosi's take on Berlusconi nixing the Buffon deal. At first I was really, really, really upset. I just could not believe he would pass up a chance at World Champ, World Class GK. Then I laughed and said the only person he has to blame is himself...have fun with Dida Silvio, maybe you can have another kid for him to baptize.