Definitely in! This sounds like a great way to see what impact a mon would have on the metegame-I just hope you choose some good pokes.
Here are the pokes I'd choose for each round:
A decent spinner-with a huge amount of Spikes(Roserade) in the metagame and two spinners-one of which is complete set-up bait for ghosts, and the other outclassed as a bulky water, I'd love to see Tentacruel. Starmie would be too OP, what with it's amazing coverage, but Tentacruel would fit nicely I think.
Sand Force Hippowdon would make a great physical wall-and it doesn't miss out on SR thanks to the new tutors. UU really needs a great physical wall that can take on SD Heracross-since all Gligar can do is Toxic or Earthquake for pathetic damage.
Those are the two I would like to see most, but it's going to be a lot of fun anyway.