Those Ogres had completely different backgrounds than the Ogres from the Mountains of Mourn. They weren't as barbaric, didn't practice blood magic, and were as dumb as a box of rocks.
I have no problem with the story moving along and armies changing but to drop entire lines, many units, and mesh together incompatible armies will kill this game. Yeah, it might attract a few new players... but do you honestly thinkm the poor lizardmen players would just pick up another army after getting the shaft (this assumes the improbable likelihood that these rumors are accurate). I just don't see them widdling down to 6 armies. Combining army lists into larger books? Maybe.