Substantial research showed that 128-player battles just aren't fun to play!

I think it is not possible to get a clear research to this point, because the game has so many other things, which doesnt make fun. 

For me it would be a dream to play a small map with 256 players.

All the "research" DICE has done resulted in a game like Battlefield 2042, which nobody wants to play. So maybe you make another research.