Not everything will magicly go faster by starting late, like reputations and legendary drops wont suddenly appear in your mailbox.
You need reputations and questlines to eventually unlock flying. Still the case for Draenor too.
The first honor prestige will go 2x faster in 7.2 but you still have to play.
AP has catchup but it still takes some time, alt catchup is faster then new starting mains in most cases.