I agree. I main Charizard in Smash 4, Project M, and Pokkén Tournament and love his moveset in all three games. The Pokémon Trainer coming back in Ultimate put a damper on me because I never liked playing as Squirtle or Ivysaur. I played as Charizard in Ultimate at E3, and while he got some buffs, I noticed you are forced to switch into the next Pokémon in line every time you get KO'd. Plus, with everyone suddenly latching onto the Trainer and saying they want to play as all three Pokémon, it really kills my desire to keep maining Charizard since I only wanted to play as him. With that said, my most wanted character by far, King K. Rool, is now playable. As such, I want to shift focus and make the Kremling King my dedicated main. I may keep the Trainer as a secondary, but time will tell what happens.
It's not that much of a big deal, just Down+B two times and you get the same character, but without Rock Smash. While I don't main Zard in any way, I don't see how him losing a single move is so bad.
Losing a single move in exchange for being forced to switch through characters every time you lose a stock can get irritating. Rock Smash was a decent punish option, and I rather have that instead of forced switching into two characters I'll never use.