The Republicans have the house and Obama does what he wants. What makes you think taking the senate would change anything?
Well I’ll just stay home and not vote. Might as well let the house go Dem too.
In theory, if the Republicans had both houses of Congress, they could get some substantial bills on the desk of the President. Of course, the President would veto the majority of them, but the Republicans could "draw some lines" with an agenda to fix what the last 5 years have given us. They may not repeal, and they may barely amend Obamacare, but they could offer something. The farther Obama's approval numbers dip, the more leverage the GOP has.
With only the House today, the GOP has far fewer options. It's like a snowball, rolling downhill, however. A trickle turns to a stream, a stream to a river, a river to a giant waterfall.
If we had the Senate we would have legislation pass all the way thru both chambers of Congress.
Obama would be under way more pressure to cooperate with common-sense legislation which made it all the way to his desk. As it currently stands Reid keeps this from happening.