This might be the flak you're expecting, but when I see locals() used in production code I've had problems refactoring it. I don't see how it's different from "from foo import *" I appreciate the terseness but looking at the code, or even with the IDE's help, I can't really see what's expected (especially if I'm looking at someone else's code). If I move things around I'll get bit at runtime--perhaps in a corner case that doesn't get caught the first time you run it.

Maybe this is the use-case you're talking about, but when I have something super generic I usually have clear and careful error handling inside. It kind of defeats the terseness of using locals(), but the goal is more about flexibility.