Even if you count players who don't use steam and optimistically say, player count didn't drop from it's peak from that client, DE still lost a lot of players on steam.
Whether it's because of a bad update versus a influx cycle of new games, remains to be seen. Though looking at the complaints in the forums, the former could be the reason since people aren't happy with kuva lich and empyrean.
I think players keep expecting more polish and less janky controls. They want lock-on type tight control instead of skyrim's wobbly fighting style. In terms of polish, they want enemies to be less horde mode and more challenging. Unfortunately to toughen up enemies by giving them weak points to shoot at, DE also needs to lower the horde count if they make this tweak. Personally I think they should keep the current horde mode and make weaknesses for enemies. I want random chance for either the standard easy peasy strawman and a harder more challenging enemies with weakpoints but significantly less enemy spawn during missions.
I would love it if DE did do what some players asked for in regards to empyrean. A bullet hell mode with waves, upon waves of bullets which players have to dodge while in their archwing. I feel like they keep missing a great opportunity to do something different and interesting.
Kuva lich could have been great if it wasn't isolated with just one planet but followed you around everywhere like how the stalkers operate. I would love to help other players kill kuva lich because it would make the game so much more unpredictable and interesting.
They keep isolating each game expansion instead of keeping them in the same nodes. Players are already isolated, but they keep isolating them even further making it harder and harder to find randoms.