there are no complicated control inputs. You will never have to do that z motion or quarter circles. Controls will always be direction, button, button + direction, or button + direction at same time. This may sound basic, but its a lot more complex in practice. There are moves with 1 frame start up, moves with high priority, anti air.
Despite having these things, the questions you are asking doesn't describe the game very well. All that stuff is helpful, but there a lot variables in this game. What might be a normally reliable anti air move might be completely worthless in one situation. The game is dynamic, in traditional 2d fighters if you do an attack, the attack will do the same thing everytime, regardless of how much health you or your opponent have. In smash its complete chaos at times. Honestly, the best way to get to know this game is to just play it. The experience is rather unique when it comes to 2D fighters. Some of the stuff I mentioned wont even come up with most players.
this game is closer to power stone than street fighter.
