Like I am all for buying DLC content when it adds something big. I am a big paradox fan which does DLC after DLC (Stellaris, crusaider kings, EU4) of content but the Festering Skies DLC seems like something that should be in the base game and it feels odd to charge for.
For a game that doesn’t seem complete this could of pushed reviews in your favor.
How do you feel that this should be part of the game? It was never planned as part of the original game’s design. This is something that was decided long after, which requires lots of development time. Developers don’t work for free. Your opinion that something should have been part of the game is subjective, but doesn’t make it true.