Not repetitive at all, actually. This time the ex-horde-warchief didn't get killed, nor did the allies get to gloat while at it. Furthermore, unlike in the previous expansions where the bad guy loses ground and key fights patch by patch, here the bad guy actually achieves his goals and becomes more powerful.
A refreshing change in story-telling, imo. Now we only need Sylvanas to be crowned the Queen of blood elves.