Which means that on a smaller plane on a full flight, you may have to gate check your bag, leaving you lined up on the gateway when unboarding.

I agree with you -- lining up sucks. What I tend to do is review my seats when I check in electronically, and if there is a decent number of open seats, I can count on the overhead space being available. If there's only a few open seats, it might be worthwhile to line up to avoid gate checking.