I agree... I don't see a lot of 752s downgraded to something else, but the 320/319 issues and even some 763->752 downgrades recently have me more concerned. When that happens, though, all boarding passes are replaced. Happened on an ORD-DEN recently and they literally had everyone come to the counter to check their BPs. I had seen the change and had a new one issued at the RCC, but they way they were talking, I had the GA check it.

Pick the seat you like on a 752, I would say, and just beware of the other kinds of changes that you could get as DHG mentions above...

...BTW, you apparently haven't flown in an E170, yet. If you had, I suspect it would be above the RJ7. And perhaps above the ABii...