Basically it would make Republicans able to block anything.. any legislation has to pass through both the House and the Senate before it can be signed into law by the President.
To get most things through the Senate requires 60 votes anyway, so that's usually where legislation dies.. the exception being reconciliation bills can get through the Senate with a bare majority (or the VP being a tie breaker).
"Budget reconciliation bills can deal with spending, revenue, and the federal debt limit, and the Senate can pass one bill per year affecting each subject." -
https://en.wikipedia.org/wiki/Reconc...tates_Congress)
The House only requires a majority to pass legislation.
So any legislation that isn't reconciliation requires Republican votes anyway, so doing something like putting access to abortion or same sex marriage into law requires a majority in the House and a super majority in the Senate (60 votes).
Which means even now doing anything except reconciliation that doesn't have support from Republicans is impossible.
Losing the House would mean more Republican support would be needed to do anything, but that's a barrier to almost everything as it is so not much would change for non-reconciliation legislation.
Reconciliation type legislation would be harder to pass but they would still do it since it's stuff like budget to make sure the government stays in operation.
Increased chance of government shutdowns when they can't all agree, Republicans will suddenly become debt hawks again, etc.
EDIT: Good point about judicial confirmations.