I agree! The airlines would do better to offer free checking for one bag and charge a fee for carry-on (and not oversell carry-on space). Then they could shave off a minimum of 5 minutes for boarding, and maybe much more (10 minutes? 15?). Saving 10 minutes in boarding time may mean one more flight/day for some routes.
Southwest should do this. They are almost the most optimized airline since you can have 2 bags free and a psuedo random boarding process. I imagine that overhead bin space is probably not as contentious on Southwest flights anyway.
