A House loss would be horrible! It would be all investigations all the time for two years. There would be an impeachment vote. In short complete stagnation until 2020.
The fickle public might decide the Trump revolution is over & “didn’t work” and go back into Dreamland with a Rat!
The House is also the origination of all federal spending. Don’t think for a minute they won’t detonate landmine after landmine once they get control of the national purse strings.