Wardom, high power > high damage any day. Plus Revenge isn't that hard to activate, just lose the previous round
If you can get her use Miss Twice Cr but if you can't Wardom's is better because he will always have 8 power (if its not decreased) and he can sometimes get 8 damage which makes him an evil 8,8. XU52 is good but his power is too low.
A first round victory with Z3r0 D34d and an XU52 in your hand = opponent will need clean panties. I have yet to try out Wardom, but against folks with a low power and high reduction abilities (Oshitsune, Tula), XU52's ability is mighty handy...
while your second point about reduction cards like Oshitsune and Tula is accurate, I'd like to argue that Wardom is better than XU52 in your first situation: "A first round victory with Z3r0 D34d and an XU52 in your hand = opponent will need clean panties"
a first round win with Z3r0 D34d with Wardom in your hand can be even better imo. First of all if you lose the second round Wardom's revenge will be activated and you will still be able to ko. If your opp opens the third round, they will still have to guess whether you play him that round or in the fourth. Plus your opp will be expecting you to throw the second round, so you can play minimal pillz in the second and win it, and then win with Wardom without the revenge ability activated.
All in all I like Wardom better