I would call them rogue, exactly. Underplayed would be a better term.
I believe Night March to be one of the strongest decks in the format. You cant come to states and play a deck that loses to Night March. As long as a deck has even just a tech that allows you to beat Night March, they’ll do fine.
I don’t think Wailord is too strong. You will win your first couple of games, but anyone who has played against Wailord before will know just to tie if they aren’t playing a deck that can do massive damage every turn and recycle energies. It will probably get you into cut, but that’s about it. You wont get much further than that. It’s a nice sleeper pick for someone who really needs their last points.
I’m torn on YZG. In my opinion it isn’t a very good deck in standard. It gets wrecked vs Night March and although Gallade helps, its still a bad matchup. The only way I can see it beating Night March is by killing Shaymins almost every turn and using techs like FFB and Pokemon like Toad and Darkrai ex to take more than one hit. Also, the standard Maxie engine is really inconsistent in my opinion. People get it out once in a while but to me that isn’t enough. I can’t play a deck that utilizes Maxies and get it out very little. However, I have seen some lists that can get out Maxies consistently. Those engines have made me rethink YZG’s potential. In short, YZG is a powerful deck when it’s Maxies engine is consistent, but otherwise I don’t believe it to be very powerful.
Trevenant relies too much on its lock. Even Night March can beat it by Lysandre’ing around Trevenants and using Hex Maniac at the right times.
Last point: I think Wobbufett/Crobat is a Nic sleeper pick. It has problems with consistency, but the Bo3 format can allow you to win when even when you dead draw a few games. It is also very powerful when it gets lots of bats on the field.