Altho Roserade suffers 4 moveslot syndrome, she can use extrasensory to deal with poison types, getting surprise KO's on mons like Toxicroak. Then only Drapion would wall, unless you want to use hp: ground.
I think the real killer about Roserade is that she can use so many effective sets. She has great SpA, decent bulk on the special side, great base speed, and the movepool to abuse it. Natural Cure with grass typing alleviates all the status flying around and leech seed stall. Besides a dedicated special wall, what really forces out a Roserade? Dugtrio seems like the only check, albeit at the cost of revenge killing.
I think the real killer about Roserade is that she can use so many effective sets. She has great SpA, decent bulk on the special side, great base speed, and the movepool to abuse it. Natural Cure with grass typing alleviates all the status flying around and leech seed stall. Besides a dedicated special wall, what really forces out a Roserade? Dugtrio seems like the only check, albeit at the cost of revenge killing.