Two weeks into this expansion, I have my druid to 85, my shadow priest to 83, tailoring maxed out on Horde and Alliance sides, and my druid's cooking, enchanting, fishing and skinning maxed out as well. This is how I can say with complete certainty that it is the professions that motivate me to level.
I already knew that was true for lowbies. Because nothing can push me through 5 levels in a sitting on a low level alt like knowing I can skill up a crafting profession at the end of it. But it is funny to see that's true of the primary characters as well.
If I think back to the launch of Wrath of the Lich King, I think I had two 80s before I did a big professions push. But this time, it was simultaneous. Yes the new phased linear questing and all the new things to see and do kept me out there and racking up the XP. But truth be told I got just as excited at making it out to Twilight Highlands and buying my first pattern (for the enchanting rod. second purchase? the lamp pet recipe.)
This has made it easy to see that the next character I need to level Alliance side is my wee shaman. Why? Because we really need a leatherworker...