Honestly feels like renegade will be different then the "norm" one to expect when reaching the endgame of a pokemon game. It will definately have this big final fight against the "renegade's antagonist" (who ever that will be) but i doubt we have to go through some elite 8 gauntlet to get there.
Dont think the renegade route will end sooner then paragon route. Paragon is the only one who has a postgame.