No, he's still be talked about. There would be a lot of debates going back and forth on that issue but that's still talking.
You seem under the impression there are enough people on each side to facilitate such a conversation, but as with the AT issue, the vast majority leans toward one side to the extent the conversation rarely arises. The only exceptions in terms of the future first-party discussion are 3H and Astral Chain, due to their lack of spirit events and promotional capacity. And the lion's share of that conversation is just who the 3H character would be, which isn't applicable to Isaac's situation.
Even if this place proves an exception (given rejecting that notion is the only way the character stays "alive"), that again hinders conversation, as most who embrace the differing opinion won't regularly frequent the thread, given they stopped believing the character to be a plausible inclusion. Like with the AT.
If people didn't stay to debate the AT issue there aren't going to be that many more who stay to debate the third-party one.
So if the only goal was to have the post count exceed 39,872 then yes, there'd be more. If the goal was to maintain the momentum, not so much.