Smash is for people that can't play real fighters. Don't get me wrong, it can be complex if you want it to be and you can still have a lot fun but facts are facts.
It isn't that complex a game. Typically you use a gamecube controller and the left stick is for movement while the right is specials, so you are probably fine as-is. Plug a nunchuck in and you are good to go.
Tatsunoko vs Capcom is the best fighter on the system. It's Capcom vs some obscure (to the west anyway) anime characters. It runs on a scaled down version of the sfiv engine and feel very much like Marvel vs Capcom. You'll need a real gamepad for that one though.
Other than that there aren't a whole lot of fighters on the wii unless you count the virtual console.