>>36557861>Does Ultra Moon rectify this problem or would it be better to just skip it?Yes it does, there's a good amount of post-game in there between RR and Utra Wormholes. Not to mention, you can get Totem Pokemon and Pokemon you couldn't get from Sun/Moon. For example, in my current run I caught a Gorebyss just after Lana's trial that's going to be a main member of my team. Couldn't do that in the previous games.
