Another thing to keep in mind is that hostile maps also discourage credible candidates from running, which in turn decreases the willingness of the opposition party to spend resources in those districts. Kind of a double whammy that makes things even more difficult for the people who do have the courage to run. Just a little meaningless anecdote, but I got the chance to have dinner with a retired congressperson from New York a while ago, and they basically told me that everyone is constantly paranoid about being drawn out of their districts and are willing to do all sorts of things ranging from innocent to extremely shady in order to prevent that from happening. Lovely thing, politics is.
I'm thinking that states would do better to scrap congressional districts altogether and adopt a proportion-based system like they have in the Netherlands. I've said before that New Hampshire - the legislature, at least - never has problems with gerrymandering because the districts are too small to draw in a way that favors one party, but New Hampshire's system would be impossible to implement nationally because then we would have literally thousands of congresspeople. But I think people care far more about which party controls Congress than the person that represents their district, which are literally arbitrary lines on a map that get redrawn every ten years (or earlier, whether a court redraws a map or someone pulls a DeLaymander).
