Thing is, they were 3 of the main people responsible for making Halo 5's MP so good, multiplayer design director, lead multiplayer producer, and lead arena engineer. Definitely worrying for Halo 6, hopefully 343 can find good replacements.
The 3 same people that made Halo 4s notorious multiplayer the worst in the series. Its often bigger than the sum of its parts. Naughty Dog had some key people leave during Uncharted 4s development. Doesnt mean its now going to suck.