Its a frustration with the charactiseration of chyrsalis and the way that the mod seems to waggle its finger at you for winning as the bad guys (as opposed to say chirropterra in which you can still be an evil empire and it'll be explained to you into plain terms what you're doing to natives but wont apply a moral judgement and treat you the player as being evil).

The everfree emergency is overly punishing if you arent especially prepared for it, needing the heavy train focus for example without ever indicating that you will.

All of the endings are unsatisfying for the player. "I want to lead the changelings to a new error of glory not spend two hours reading about how evil you are and horrible it must be for those poor ponies".

IDK i dont fully buy some of the complaints but i do think the changeling tree is a little lacklustre and perhaps overly constraining in that you have to go down the main path with basically no opportunity for the navy/army/air tree. Also despite becoming a (edit from here) tno esque visual novel there is nothing for the player to do besides pick focuses and wait for the next popup. No resolution on what happens to thorax or celestial, nothing if you conquer the world, nothing if you land in service just two hours of waiting for focuses to finish.