Yeah, rmc conversions have transformed the worst major coaster into the best. And by looking at the current line up, I imagine it was already one of the better coasters...
I might be wrong, but the Joker generally has to follow the footprint of Roar, meaning the compactness of the coaster has already been pre-determined by GCI. This would normally be ok, but the park really don't have the space to play with and after seeing what rmc have done with Goliath at SFGA, rmc could have built a (brand new) similar sized coaster to Joker, in a smaller space. (while saving Roar)