First tier? Like Deval Patrick? Martha Coakley again? Tim Murray? Bill Galvin? Joe DeNucci? Barney Frank? Nikki Tsongas? John Olver? Ed Markey? Am I missing someone?
Tim Cahill maybe, but I don’t see him winning the nom after running against Patrick.
Sadly, any of those RATs might win in a presidential year. You forgot about Meehan, Tierney and Robert Reich. And you didn’t mention Lynch or Neal, perhaps because they are (at least nominally) pro-life and would have a hard time winning the Dem nomination. But any of those Democrats have sufficiently high name ID that they will be tough to beat in a presidential-election year. Brown was able to ride a perfect storm to win by 3% in a low-turnout special election, but he will face a much tougher environment in 2012. Whoever wins the Democrat nomination will start off as the favorite.