no if your main is horde alliance mounts still count, just not the ones that arent unique. most mounts are unique only a few arent. like i have the queldorei steed so if i log on a horde toon it will turn into a sunreaver hawkstrider so the sunreaver hawkstrider doesnt count, however if i buy a stormwind horse on my alliance it doesnt turn into a wolf on my horde so if i go and buy a wolf it will count.
---------- Post added 2013-03-30 at 06:15 AM ----------
leveling up entire characters isnt quite the same as spending gold on a mount. at most the average person will only need two characters to get this achievement 1 horde 1 alliance which most people have
---------- Post added 2013-03-30 at 06:17 AM ----------
yeah i quite like the new mounts, the blades are awesome