A loss is a loss. Margins shrinking are good, of could, but a red seat remains a red seat regardless.
But a loss isn't really always a loss. If this shows a dramatic shift to Democrats, but we still lose the election (which we were never predicted to win), then we have a nice long list of actually winnable seats with that margin that have a good chance of shifting to the Democrats in 2018.
This seat is basically meaningless as far as governing goes, so winning or losing isn't really that important. Nothing Ryan puts forth is only going to pass by a single vote that this election could have decided, that's not really how the House works.
Closing the gap by only 5 points (Cook partisan lean has the district at R+11) is more predictive of small Dem gains in Congress, not the kind of 10-point swing that would gain us the House, I think. But I'll wait and see the results and what the experts say about it.
This isn't the only election, it's one data point. State seat margin shifts have been bonkers the last few months, and Georgia is a big one to watch as well, since that one could shift way more than 5.