Smash 4 has already proven to be pretty fun to watch, and while that could just be because it's brand new, I think it's more because the character play styles are extremely diverse. For everything Smash 4 lacks in terms of competitively favorable mechanics, it makes up for in sheer variety.
That's just something that happens when everyone is forced to pick a different character.
If a certain character is discovered to have a complete advantage above everyone else, you can believe people will choose that character when in a play to win environment with money on the line.
Most of the fun in the invitational for me was seeing the game for the first time at a tournament that Nintendo was actually hosting with actual pro players playing the game.
But for the most part I was just waiting for the grand finals when we could get to the real meat of the event, and that was a bit soured by the way they handled who won, but still.