Obama applauds Democratic sweep
The most interesting thing about Obama's statement is how quickly victory gets translated into a story about unity. A sweeping win like this is rarely read the same way by both sides. Democrats will hear a mandate for their agenda, while Republicans will point to specific races and local issues rather than a wholesale rejection of their platform. Both readings can be true at once, and that's the part worth keeping in mind.
Control of both chambers changes what's possible in Washington, but it also changes the incentives. The president still holds the veto pen, and the two parties will have to decide whether they want a season of legislation or a season of standoffs. Obama's call for leaders who offer concrete solutions sounds good, but the real test comes when the new Congress actually has to pass something.
I'd want to know which districts flipped and what issues drove the turnout before I put too much weight on any single interpretation. The message voters sent may be less about unity and more about priorities, and those are different things.