It's all about phrasing and intent, you can suggest things and give feedback without sounding entitled or coming off as a douchebag. Any person with common sense would know this already.
For example, if I wanted to suggest to Neon to add a certain fetish/kink to the game, I would say something along the lines of:
Hey Neon, I have a suggestion. It would be sweet if on Mason's path with the pet-play stuff, we could have the option to walk him around on a leash. This might make more sense on the corruption path, but I wouldn't mind it on the romance route either, as long as it makes sense.
Notice how I suggested something, without coming off as entitled, douche-y, or without insulting the dev or other players? Well... only if everyone could do this.
So yes, feedback, critiques, and suggestions are completely fine, and in most cases welcome. Just be respectful about, the dev can decide what to do with your feedback and suggestions, and I'm sure Neon appreciates it way more when it's done in a respectful, less demanding manner.
That's all, peace.