Competitively I can't see this happening, without some sort of indicator made to show what characters would possibly be picked, and even then there are problems.
Random-select, in-terms of the fighting game-circuit, is generally meant to confuse-opponents and their character-choices.
Apex actually forces anyone that wins with a random-select to play random-select again for the next round in a set.
In Smash, unless you were good with nearly everyone ala-M2K, it usually wasn't a feasible option. With an advanced random-modifier for characters, character-counterpicking would be removed, and an entire element of the metagame with it.
Considering the Project M dev-team is known for catering to the competitive-scene before the casual one, I can't see this happening anytime soon.
There is an addon-system as of 3.5. Maybe someone else (aside from the dev-team) could make one.
Who knows? Maybe everyone would use it at Apex. Maybe Smash 5 will have it. I'm just saying that I don't think this is in the cards.