Coming back through ATL yesterday, departure was delayed due to late arrival of FA's. Gate agent took innovative approach to "speed" boarding of our 757 by loading from rear forward and FC last. Alas, it didn't seem to work too well as late boarders and standbys were still getting on 15 mintes after scheduled departure time. Give agent an A for trying but some FC did not seem too happy as they were worried about storage space. By the way, the second door was not used for boarding or debarking. Problem??