The game. Im curious? what made you don't like the game itself.
Personally these are the things that make me worry about what the future of the game is going to turn like and whether or not it's worth sticking with for a long period of time instead of just staying on Project M, everything else in the game outside of the mechanics I'm completely fine with, especially the custom moves.
-No shieldstun or shield damage, low shield degradation and a fast recharge rate means that shields are a pretty powerful option, there's not really a point in approaching someone with many of your moves because you'll end up at a frame disadvantage and get punished for attacking, better to just abuse projectiles and wait for the other player to make mistakes. Promotes a playstyle I don't particularly find fun or interesting.
-Highly spammable rolls and a lack of dash dancing means that tech chasing is almost non-existent, which was always something I found really fun in previous games, trying to read where the other guy will roll and being able to extend the combo if done correctly was a great feeling, but the window you're allowed to be able to do this in is massively reduced.
-Multiple air dodges/very little time between air dodges, I do not like smash 4's air dodge system at all, it requires you to put practically no thought into air dodging whatsoever other than "maybe don't do it near the ground, I might get punished", makes recovering super easy (which factors into my next point) and juggling practically non-existent.
-Characters live for ages, the mixture of massive blast zones, floaty physics, multiple air dodges and the new ledge mechanics make it super easy and safe to return to the stage, in competitive smash a comeback usually comes around due to a good edge guard, I don't see that happening very often with two good players, which I don't find particularly interesting.
-Certain moves still have questionable design, I don't like it when moves are practically useless, Mario's FLUDD is a move that shouldn't exist in it's current form, Megaman's Leaf Shield shouldn't exist in it's current form, Mario's dash attack is an incredibly unsafe move due to high endlag but you get nothing for actually hitting someone with it because the end lag is too large for any followup and so every other grounded option he has is better and you should be using one of them instead of that move.
-Techable grounded Meteor smashes/Spikes. In previous smash games it would instantly pop them up in the air if they were on the ground when you meteor'd them, but in this game it must apply some amount of downwards knockback first, meaning that a character can tech it instantly without moving off the spot and punish you (due to meteor attacks generally having high lag) just for successfully hitting them, I've been in sudden death before and hit a CPU with Mario's Fair, but they just instantly teched it and hit me with their own Fair whilst Mario was still recovering from the move, it's ridiculous that the game lets you do that and it limits a players options.
-In terms of general physics, I've never liked that momentum conversation stopped being a thing after melee, Smash is supposed to be a physics-based platform fighter, right? Any other platformer that had physics where your jump distance was exactly the same regardless of whether you were running or not would be considered stiff and I'm not sure why it's something that people apparently don't notice in Smash.
I'm interested in seeing what the game is like when playing with actual people, but these things are all part of the game and I can only imagine the game will become less interesting as people get better at it, because they won't be doing the risky, more fun stuff and will just generally be trying to exploit the powerful defensive options, which has never been what I've wanted out of Smash, as a 64, Melee and Project M fan.
For me the fact that custom moves exist is infinitely more interesting to me from a competitive standpoint than the base game mechanics, just because they're something new and interesting to me whereas the base mechanics have got a bit of a "Oh, here we go again" feeling to them.
I mean, I really do hope I'm wrong, I'd love to be able to starting working on improving at the new game but based on what's there at a base level I don't know if I'll be enjoying the game 2-3 months after the WiiU version releases, it's very possible that I'll have lost interest and gone back to PM as my main game.