I admit I did pull that number out of my butthole. But generally the early levels of wow do have 4-5 level gaps where you get no new abilities, useful gear or gameplay functions. ARR might have a longer global cooldown but at least I don't have to stick with a two button rotation even after my level hits double digits *cough* hunter *cough*.
I may be wrong but I really don't believe that with quests, hunting logs, fates, guildhests, levequests, duties, challenge log and deep dungeons ARR levels slower than wow.