What would be your definition of competitive viability then?

A competitively viable game reliably determines the better participant within the upper limits of its players's capabilities. While auto racing is competitively viable between human participants, it is not competitively viable between optimized AI drivers. Catch is competitively viable between untrained 10 year old children, but would largely be test of luck if played between two professional MLB short-stops. Likewise, Smash 4 can be competitively viable between novice players, but it is too circumscribing for skilled players.

melee is faster paced than smash 4.

And that isn't what makes Melee better, it's interactivity. Smash 4 doesn't add anything to Smash Bros. that makes it more interactive than Melee. A turn-based version of Smash can be more interactive and competitive than Melee.

Also saying smash 4 recieved attention from Melee by proxy is a huge generalization.

That's not a huge generalization. Melee had no competitive community before its release but was played at national tournaments by the time Brawl was in development. When Brawl was released, it was tried at the national stage and massively flopped. Brawl then was responsible the near-death of the competitive Smash community, which can thank renewed interest in Melee and Project M for its resurgence. If Smash 4 was Smash 2 coming off the coattail of Brawl, there would be no tournaments for it.

IsStreet Fighter 4 big now simply because Third Strike was so competitive? Absolutely not.

Street Fighter and Smash Bros. comparisons are abysmal. For one, Street Fighter is intentionally designed to be a competitive franchise, while Smash Bros. is intentionally designed to not be a competitive franchise. Moreover, Street Fighter 4 is a defensive game with many embedded defensive options. Smash 4 is a defensive game that has shielding and air dodging. A defensive Smash game is less comprehensive than a defensive Street Fighter game.

Trash, who I believe is one of the smartest posters on Smashboards, has this to say about defensive game play by comparing Street Fighter and Smash Bros.

timeouts are best in scenarios where there's smart interactions. think SF4, america's most hype player times people out all the time, to the point that it's his evo moment. but the reason timeouts there are hype is because snakeyez is constantly working the opponent, and you can actively work your opponent in street fighter without actually dealing any damage. there's no similar comparison for smash games, period.

I wonder, if Smash 4 was released with Melee's game play, would anybody argue that it should have been more similar to Brawl?