Rosalina is considered broken by top players so I wouldn't say necessarily Wario is a bad character (but yes I have never won with Wario in public, online is a different story).
I mean, Sakurai got Wario right in a lot of ways.
His odd characteristics of being a heavyweight (with power and weight similar to Ike), yet an aerial master is a very Wario thing to be. Wario's nearly invincible in both his games and SSB4, yet he gets around without his bulk bothering him in the slightest.
Wario Land is also all about using your abilities and environment in creative new ways to reach new platforms or defeat enemies or break through obstacles. Three of his specials are recovery moves. Bike can also be used as a projectile in different ways, and the way you ride it is very versatile as well. Chomp can be a command grab, but it's also useful against projectiles and gives a unique counter against explosives.
Wario has very cheesy villain malice in everything he does. He's rude, his most common way of emoting happiness is an evil laugh and he's not above being vulgar. So of course he's the only character in the entire series with four taunts.
Similarly, because Wario's appearance is so different between his two titular series, he's the very first character to have an "alt skin" that actually changes his model rather than just the textures.
His classic "W" pose is in two of his taunts and one of his victory animations, and I think it's pretty endearing. Wah, wah, waaahhhh! I feel is almost as iconic nowadays as "show your moves!"
Anyways, if you REALLY want to see Little Z kick ass with the character, this is his far superior montage. Has great music too, was pleasantly surprised to hear Savant in a Smash montage.
