Epic Struggle is kind of silly, since it requires you to be winning the game in order to win the game. I've never seen a deck based around Mortal Combat, but I can picture it working better than Door, in a Fluctuator deck at worst, or perhaps with Hermit Druid...
Now Test of Endurance I have seen work, and work well. It was still a suboptimal deck compared to what could be done using Oath of Druids, but it was an interesting creation and I nearly lost a casual tournament to it, in the final round. I got first, but the guy with the Test of Endurance deck did get second. That says something for it...
Coalition Victory is as bad as Door and possibly worse. No argument there. Believe me, when Invasion came out, I was taking shots at Victory whenever possible.
