I don't mind the Shadow Tag suspect, since Gothitelle tacked onto a dancing/HO team is hard to play against.
But for Mega Sableye, I'm actually disillusioned because when I complained about it in the beginning being centralizing, nobody gave a shit. I did the same 'I told you so' with Lando-I and nobody batted an eye until the Aegislash suspect test brought it back to light.
But now is different, since M-Sab isn't even a big deal anymore and there's a multitude of ways to take care of it from Serperior to Keldeo to Charizard to any Fairy. Sheddy Stall is annoying, but I'm more willing to blame Baton Pass existing on Shedinja, since it was specifically retconned out of its learnable moves after the introductory generation.