The catch-up contribution thing just doesn't seem like a big deal. That's something that approximately zero Mustachians should care about. Oh no, you can't deduct an extra $6,000 when you're over 50, earning half a million dollars per year, and somehow not retired yet.
Combining the 457 limit with the other plan limits so that public employees can't deduct $36k anymore sounds like something that would affect a lot more people on here. I have to say it's always seemed strange that you can do double retirement contributions if you work for certain government agencies. If I were king I'd take it a bit farther and eliminate all but one type of retirement account; there's no good reason for 401(k), 403(b), IRA, SEP, 457, etc. to all be things with their own little quirks. Just let everyone with a job put away money in the same kind of account with the same rules for everyone.