
OK, I'm not a hardcore RP'er or anything, but to me, this is a fairly significant break in the fourth wall, blurring the lines between WoW and real life. It's a question of suspended disbelief, a literary tool that helps us immerse ourselves when watching movies or playing video games.
You might argue that the current flying mount is a roflcopter with jet engines attached, but at least 1) it comes from existing Warcraft lore and 2) nothing designed like that would actually fly in our world, so it still "fits" the genre IMO.
There are tons of different directions Blizzard could have gone with this - there are lots of great steampunk and DaVinci-esque inspirations a mechanical land mount could have taken on. To me, a recreating a motorcycle just shows a distinct lack of imagination.
Flying carpets, on the other hand, get the Shamantic thumbs-up.