currently, social cripples stuff it up for everyone[1].

The trouble with your "solutions" is that they ignore that aspect of the problem and assume that if you just point out to the social cripples that they're crippled, they'll somehow cure themselves. Somehow I think that most people who have decided "sod everyone else, I'll block the aisle if I want to" are not going to get out of the way just because a light flashes.

If you added solenoid locks to the bins that would work, but cost a lot of weight. The airlines have probably done the money numbers and decided that it wouldn't pay off.

What would work is dual loading - people get on at the back and off at the front. Most would probably decide to sit at the front (to get off fastest), so you'd only have to solve the problem of people demanding to get off at the closest door instead of having to walk the length of the plane like everyone else. Probably answered by not opening the rear door until everyone is moving.

This is more likely to happen with the new double decker planes, where loading 600 people through a single door is just not going to work. They're rebuilding the loading bays for them, and IIRC they've gone for 4 or more loading ramps in many places.

[1] tautilogically speaking. Note that the statement is doubly true - not only do selfish flyers make life harder for other flyers, but all flyers are fscking up the planet by choosing the least environmentally efficient mode of transport.