I see people actively ask for crossplay and I understand why, don't get me wrong. But I don't know how it's gonna work with mod support. If it's going to be very basic stuff, almost like fortnite's UEFN, I don't think I'll like that.
KF2 mods were upmost okay-ish, Halo weapons are incredible but there's zero EU servers with them and even then, most people wouldn't play on server with no xp, which is another problem with mods.
In 4k hours of my KF2 playtime, the most fun I've had playing maps, ported from other games (and we still can't even make custom music for maps in KF2, while we could in first game!!!). If I woudn't be able to do that in KF3, I'm done.