We're bringing Shaymin back down, why not, but for sure we'll run into exactly the same issues as when he was banned a few months ago. Seed Flare's SpeDef drop will still remain problematic.
It's good that Yanmega stays in UU, he had no place in NU.
Regarding Dugtrio, something should need to happen, especially since recently Dugtrio's movepool has ridiculously increased by gaining an inappropriate access to Endeavor, among other things