2v8? Nah… How about 5v5?!
Huge map, 14 gens, 4 exit gates, 10 players, 2 teams.
The red killer hunts the 4 blue survivors and defends the red gens. And vice-versa!
Opposing killers can attack and stun each other. Opposing survivors can body block and sandbag each other.
There are red and blue versions of scratch marks, loud noise notifications, auras, generators, totems, and exit gates All other assets (like hooks, chests and pallets) are neutral and usable by all.
And the best part is that the vast majority of perks and add-ons would work just fine as they are now - no need for major overhauls in the name of balance! Yes, there might be some slight modifications, but really It’s the exact same game as normal with the added variable of interfering players.
I think that if new game modes were ever introduced, this would by far be the easiest one to start with!