I'm a bit puzzled why it should make such a big difference. Even with a Democratic majority, it appears that with pretty well everything that majority has tried to do, the minority opposition has been able to stop it in its track. Presumably the same would be true if there was a Republican majority now. You'll still have a gridlock.

I would imagine that one consequence might be to bring about a reaction against the victorious Republicans which would help Obama get back, and give him a majority in Congress in two years time...