The end of 2 seems to imply that Michael burned down an empire with his paranoia. Then in 3 he's a benevolent rich guy trying to buy his way into heaven. So, I suppose it depends on which storyline you choose. This is why so many people hated 3. It doesn't even seem like it's Michael Corleone. I believe Michael was loosely based on both Bonanno and Genovese.

"...the successful annihilation of organized crime's subculture in America would rock the 'legitimate' world's foundation, which would ultimately force fundamental social changes and redistributions of wealth and power in this country. Meyer Lansky's dream was to bond the two worlds together so that one could not survive without the other." - Dan E. Moldea