I'm genuinely surprised they want to bump staff up to 800 people. I mean holy shit. At one point they said a couple hundred is as big as they'll get. Hopefully they can manage it so their artistic quality and innovation don't suffer. When studios get that big, I imagine the gap between leads and grunts grows wide enough that communication between the two suffers.
Its big alright, but I always understood this as 200 per team, and per project.
If they give each team reasonable enough freedom to operate without too many dependencies it might not ruin quality too much, but its bold.