There's plenty of games I'd rather see than Pokken, but I wouldn't be disappointed if that's what it is. Definitely could see it being fun.
How can you imagine it being fun? Or, more specifically, being fun in a distinct way? Most traditional fighters are very similar and only have a few distinguishing factors, like input/combos style, special meter/supers usage, juggling, and shit like Soul Calibur's infamous ring-outs. I loves me some Mortal Kombat, but that comes with a nostalgia factor and an established love for the characters spanning between MK1-4. I'm sure that Pokken will do whatever it can, even unconventional shit, to set itself apart from the crowd, but if it's a traditional fighter (which I expect it to be), then I'll be excited when I understand how the gameplay itself could be fun, regardless of pokémon characters.
You see, if you would have given me Pokken when I was in 7th grade, I would have done all kinds of shit to your winky, but that part of my life, when I simply couldn't get enough Pokémon and I was dying to play a game with 3D Pokémon in it, has long passed. You're not going to reel me in just because the cast of characters. In fact, when I first saw my first Pokémon Stadium screenshot featuring a Charizard and a Blastoise, I went absolutely fucking nuts and couldn't WAIT to as much as see it in action. I annoyed the shit out of all my local video game retailers daily, asking them if they knew "when Pokémon Stadium is coming out." Until then, I imagined what the gameplay could be like, and always pictured it as a real-time fighting game. Basically, I thought it was going to be what Pokken could potentially be (though that game's roster seems reserved to Fighting types). However, again, my Pokéboner has long since died down, and I've seen plenty of 3D pokémon over the past 15 years, and even played as them in various Smash Bros games. Pokken is going to have to do a lot to win me over.