Lowrie is a second baseman trying to play a role that requires a SS/3B. He always did his best work at second base. If we hadn't had Pedroia, or if Pedroia could play SS or 3B, Lowrie would have been healthier and more effective here.
I held out hope that Lowrie could at least be Michael Young bad at shortstop, but I guess it isn't to be. He can play up to that level for awhile but his body can't sustain it and it gets him hurt. The best thing for Lowrie is to get him to a team that allows him to play second base. I like Melancon, IIRC he's succeeded in the AL East too so that's a plus. Good trade IMHO..
In a word, Punto is Alex Cora, with the ability to switch hit. That isn't a terrible thing to have on your bench. Punto has some nice bench speed as well, not worldbreaking, but useful. I can see why the Sox went after him, especially considering his OBP over the last few seasons is very steady and respectable for an MI.
In short, not a superstar, but we aren't paying superstar dollars, and what he does do he does pretty well. The big thing is the combination of a decent OBP, speed, and good defense down the middle. Punto is kind of a prototypical bench MI who can get his job done, no one needs to scoff at the signing. Just don't bat him 4th.