If we're still talking about it, I'd like to throw my hat into the ring of Assist characters as DLC fighters.
In all honesty, I think it could work. I mean, there's plenty of examples to go by when we look at other fighting games. Android 17 was just a helper to Android 18 in FighterZ up until just a few weeks ago when he debuted as his own fighter next to Cooler, not to mention Skullgirls' DLC voting campaign was full of characters that were already shown off to be assist characters to other existing fighters (Andy Anvil aids Peacock, Samson could have fought on his own), and Lab Zero was willing to take those risks. We can throw the "Assistants can't be fighters in the future" argument not into the pile of "My opinion is right, and if you disagree, you're not a true fan" fandom rules, and instead into the "Both sides have clear, credible arguments and only time will tell if they bear fruit" pile.