Very, very interesting match-up. I always thought that The Warlord's prime was during his second stint with WCW starting late in 1987. Sure, this lasted for less than a year (before he and The Barbarian went to the WWF as The Powers of Pain), but there was something special about him during this time (it was probably the booking and his cherub's face).
But, Rick Rude was the man during the late 80s and early 90s. Furthermore, unlike The Warlord, he actually touched the main-event in the WWF and was a main-eventer in WCW.
So, I'm giving this to Rude, although, if you took both of these guys in their prime and put them in a ring, I think it would be a match that most would underestimate the value of.
Pick: Rude