The two that come to mind immediately are Arthas and Sylvanas.
Killing Arthas, I could see something like “You would think, with your setback in Icecrown, you would not be so foolhardy.”
probably egg on about losing Quel’Thalas
At the start of a match: “Look who finally came out of their Undercity.”
@icyvveins also came up with one better than anything I could think of:
Arthas: “Do not fail me, Minion.”
Tevruden: “I take no orders from fallen kings.”