Locormus
Can we please get the older, old forum back?
Well the thing is like I said, due to lack of appearances under trainers especially in recent years since we never saw Swampert again in the main series under a trainer after AG and it's last sole appearance was in DP as a wild mon, we can't exactly fully determine what they could have a potential "Ash's Swampert" use in its moveset except for the usual ground move since it doesn't need the earth shaking moves and Mud Shot and Mud Bomb are perfect for it so either one of them will likely be there and some sort of physical move which looks likely to be some sort of move requiring its fist. Another thing to note is that idk if the anime will consider type coverage in the moveset.
It's been so long since we saw Morrison and Tucker so I'm sure as hell not basing of speculated movesets on their versions of Swampert. What I did is simply a projection of what I personally want to see (keeping in mind that the animé usually features mixed movesets), what fits with Swampert's regular level-up moveset (with maybe a TM/TR thrown in) and what would help it standout and help it along.
If I envision a bulky Swampert engulfed in waves completely wrecking an opponent -basically hulksmashing Pokémonstyle - as opposed to blasting an opponent with yet again an overdone blast of water, then I'm picking Waterfall over Hydro Pump, Scald, etc. There's not enough recent conjecture that would be compelling to say otherwise.