They just made it so you can solo LK (and any pre-MoP boss that drops mounts) as a crappy geared toon.
Also, Galleon and Oon used to be 24+ hours, but now they are 2 or so hours, so your point is invalid regarding the BC world bosses.
Also, the BC world bosses drop BoEs, Blizz probably kept them 24 hours to get the items for tmog rare.
As far as I know, MoP world bosses don't drop BoE gear.