Tell you what, shall we compare him to Bolvar?
Let's see...
He's a powerful warrior and utterly devoted to his king and kingdom; vowing to protect the young Anduin until he can take the throne.
Yet he failed in his duty, as he was manipulated by Onyxia and allowed Anduin to be captured by her.
He is sent on the Northrend campaign and is ambushed at the Wrathgate by Putress; who "kills" him with the plague.
His body is then destroyed beyond recognition by the dragon fire.
The Lich King retrieves his body, still alive, so that he can torture him extensively.
By the power of the light, he manages not to break.
When he's saved and Arthas is killed, knowing there's no place for him in the world anymore he makes the ultimate sacrifice and allows himself to be locked in eternal mental battle with Ner'zhul in an effort to keep the Scourge in check; yet neither him nor us knows how long he'll be able to do that for.
Now what did Thrall go through exactly? Oh he was held as a prisoner once and abused a bit by his overlord, then in 4.2 he got a bit insecure. Then he saved the world and settled down to make a family. Yeah fantastic, tons of weaknesses and strife there.
How about he fought in a most gruesome battle since War of the Ancients?