That's just wrong. During the entire leveling from 80-85 you only saw him twice, once at the Maelstrom where he said "Hi!" and once in Twilight Highlands in a fevered dream caused by a faceless monster. In the Firelands patch you saw him in the trailer and then for the wedding event, that was it. FL had Malfurion as the main poster boy. Sure, Thrall was all over 4.3, but that was it really.
Oh, and I suppose, he played an odd role in the second half of the goblin starter zone.