I only worked long haul, mostly international so I was never on an airplane that didn't have them. I actually wrote it up and talked to a supervisor. I thought there should be changing tables in ALL the lavs. "For crying out loud, it's a plank of wood! It doesn't bother anyone not using it and how difficult/expensive can that be??" Wouldn't it be nice to just be able to use any lav on the aircraft to change your child??
Needless to say, the airlines don't really listen to their own F/A's but they do listen to customers. You need to write it up, if only for the other parents flying the same route.
I used to use them for my makeup after the break lol!