Oh, absolutely. We'll see what happens once we get more data, I suppose.
I do wonder if people would push to ban more characters next should Steve and Kazuya be banned? If the argument is "they're toxic/make people quit the game" then characters don't need to be #1 or #2 in order to be banned (and many people don't even think Kazuya is top 3 and
still want him banned). This is one of the reasons I don't like the argument from viewerships/attendants, since that could easily apply to characters like Sonic, ROB, and Min Min as well. If all Steve and Kazuya mains switch to Sonic/ROB/Min Min/Olimar, would people be happy? Rhetorical question, they wouldn't be.
If a character is really, really broken (like Brawl Meta Knight), then I think you could have a strong case for banning them. I don't think Kazuya and Steve are there yet. Who knows where they'll be in a year, but right now I don't think they're close to being ban-worthy.