@cicerone imposter,
Congress is held mainly as a consequence of redistricting. I don't see how that changes in any immediate way but if the down ballot races reflect what I'm guessing will be the results in Nov, the Rs will lose seats and that helps.
On the negative side, I suspect that for some time, the GOP will go further right (as the Cantor types are increasingly rejected for serious extremist of the Freedom Caucus variety) they'll become even more intractable.
The Koch crowd, as their weekend parlay demonstrates, are pushing their money and considerable organizational clout down ballot, particularly to try and hold the Senate. We'll have to wait until Nov to find out how this all shakes out.
After that, our best hope is for enough voices on the right come to similar realizations as Roy (noted above). Another WH loss along with another big loss in the popular vote ought to help. No easy fix. This is deeply institutionalized now.