Without beating a dead horse, the game needs private lobbies and the ability to choose missions freely like VT2. There should also be a much bigger offering of missions to pick from; perhaps a rotating pool for each difficulty type. That said, I actually quite like the mission board and paired together with private lobbies, it would give players a lot of gameplay choice and freedom.
I am a little concerned about the next point. As for the evolving structure of Darktide and assuming it will function like most other games with seasonal reward tracks and new playable content, please please please do NOT phase out older rewards or, even worse, phase out older missions and content when launching new seasons. Players who buy Darktide two years from now, or take extended breaks from the game, should be able to come back and enjoy the full narrative and all the awesome stuff FS releases, without feeling like they missed out or they have to play. I see a lot of influence from Destiny 2 in Darktide, but sunsetting should be completely out of the equation. It just feels so bad for players, both new and longtime.
Battle Passes and the like are best when players can pick and progress the set of rewards at their leisure; I think the Halo MCC/Infinite model is the ideal way to do it. Keep all previous seasonal content available to unlock and purchase. This also applies to the cosmetic shop. Having access to all released cosmetics, and at the very least matching bundle costs to the aquilla bundles, would go a long way. I beg of you Fatshark, let players give you money and play your content of their own volition instead of forcing them into a rat race. The VT2 model was awesome.