Yuuzhan Vong are incredibly susceptible to energy based Force attacks; something Ragnos should be capable of unleashing.
Furthermore, his showing against Luke are overblown; Skywalker had just finished fighting his way through an virtual army of Yuuzhan Vong, and slayed nearly a dozen[?] Slayers on the way - one Slayer being enough to more or less stalemate Durron [with circumstances], and 3 capable of utterly wrecking him. No way is anyone going to tell me his Force reserves weren't taxed to a solid extent.