Actually, I read Heller as coming out pretty strongly against blanket bans of weapons by category or type. Another AWB would fall under that criteria.
I'm no lawyer, but an AWB fashioned after the 1994 one may not. Prohibition of certain features might well be allowed- you can have an AR-15, but you can't buy new 11+ round magazines, have a flash hider, etc. The gun itself isn't banned, what you can put on it might be.
Either way, any AWB, if it actually becomes law, would definitely be buying a bunch of lawyers a bunch of nice homes.