If it operates on a pool of lives, you could have some folks draining the pool.
If scoring is similar to Warzone, teammates could end up taking all of the points (especially once vehicles come into play).
Given such a large group, you might end up not seeing any action, since the maps are so big.
And given that it'll be designed with eight people in mind, I'm really hoping that you're not racing against the clock if you're in a smaller group.

And I'm really hoping that it's not forced Matchmaking.

Lots of unknowns, but I'm hoping to be wrong about it all..