@Thanotos Omega
I want to say that they’ve technically already made two Mega Man fighting games (though they were released in arcades only), but those were more or less just regular Mega Man games with slight fighting game elements (the second game notably introduced the Mega Upper, the uppercut move Mega Man uses in Marvel vs. Capcom and Smash Bros).
As for a full-fledged Mega Man fighting game that plays like Smash Bros., I don’t know. Closest to that I can see happening would be a “Nintendo X Capcom” crossover fighting game with Smash Bros.’ gameplay, possibly with an emphasis on Mega Man characters due to the series’ history with Nintendo.