I think that everyone, console and PC players alike, agree, that crossplay should be off by default.
No news yet as to whether K&M will be allowed on Console. I'm sure that will be the next discussion point.
From my perspective, have been playing Sniper Elite while I wait for BF6 to launch. The Crossplay lobbies are infested with (I think) aimbots and wallhacks. Not very enjoyable for Console players. The Console-only lobbies (when you can find one) are fun and sweat-free. I can't really tell who is using K&M or controller.
I know that there are plenty of players who want only Controller players on Console. One solution is to give controller users aim-assist, and K&M no aim-assist.
K&M users don't have aim-assist, thankfully. That's only for controller users. In order to keep cross-play fair for all, it should be input-based match making only. This is what most seem to agree on, and I do as well if cross-play is to remain in the game.
Mouse and Keyboard should have been discussed by now if it was going to be implemented. The game is supposedly releasing in the Fall? The devs never talk about adjusting the aim assist, other than making it "feel better" for controller players, never about the balancing of it. How many times are we going to go through this cycle? MnK was mentioned as a possibility ages ago for the last game, but then no follow up. There's some lengthy threads on here asking for it. BF6 is in the later stages of development, right now being polished up, and game loops finalized. No way are they even thinking of adding MnK to Console at this point.
To your point about PC lobbies being infested, most lobbies are crossplay, with console players making up the majority in my area. Controller players consistently top frag with ease. I've played games in my past where you could report cheaters to the devs indirectly, and then watch them get added to a list of shame for cheating. I personally reported several cheaters that were ultimately added to that list. You can tell when someone cheats because there's something not human about either their movement, predictions, or aim. Console players feel like cheaters to me, it always reminds me of how it felt playing these cheaters back in the day. Franky, aim assist today would have been considered a "soft lock" a decade ago for most PC games. Now, it's just common place and people have come to expect controllers SHOULD be able to compete with a Mouse. Which is absurd.
