I think this year is inevitably a retooling year. I think Sweeney deserves at least a year of awful hockey to try to put the foundation together for the team he wants.
So: Stay away from bad UFA signings. No Oduya. No Franson.
For example, it's not clear to me that Franson is an obvious top 4D guy in Boston. If he isn't, we shouldn't spend on him. Give Morrow a chance; let Krug step up. Let Kevan Miller finally show what he can do.
Thus -- stay put, no panicked or dumb UFA signings, retain some cap space flexibility, and be prepared to really suck this year (inevitable with the current D). Ensure we have a viable #2 goaltender to takeover when Rask has a mild psychotic break mid-season, draft an elite D and an elite F in the top 5-10 in 2016 (with ours and SJS's 1st rounder) and come back hard in 2016/17. There will be better UFAs (plus Shattenkirk will be easier to acquire from the Blues, for example, because he'd only have 1 year left on his contract), Kelly will be gone, Pasta/Spooner/Krug matured, and some of the 2015 prospect class ready to contribute, Krejci/Bergy/Marchy, still prime, and hopefully Chara still has something left in the tank.