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.
Nothing to worry about. Halo 5 has already set the foundations for Halo 6 multiplayer. There isnt as much need for them. They fixed the MP where H4 failed. Went from the worst MP in Halo history in H4 to the best with H5. All H6 has to do is do eactly what H5 does.
That's true. As long as they copy Halo 5's MP formula, they should be fine. That being said, there are some things they can do better with Halo 6 MP imo, better playlist selection at release and less forged maps/more made from scratch maps.
Singleplayer is definitely the biggest concern for me with Halo 6. I really don't like the story direction Brian took the series in with Halo 5. If they want me to be interested in Halo 6 SP, they're going to need to a. make Arbiter playable again (3 teams? Arbiter, Chief, and Locke), b. give us an equal number of missions for each team and better character building on Blue Team, and c. bring back Halfjaw (Rtas 'Vadum) and Lord Hood.