I don't know if you'll see this, but my friends and I really enjoyed the 128-player BT. It immediately became our go-to mode and it was honestly a bit sad to log in today and see it gone. I'd love to see it readded to at least the rotational game mode pool if not (ideally) permanently alongside the 64p mode for those that prefer it. The two play so differently that they don't really compete with each other in my opinion.
I know it's a bit divisive on social media, but in-game the lobbies filled up faster than 64p BT on a normal week even with twice the player count so it seems to be quite popular. Although I'm sure you have a better idea of the real popularity.