Come on, this is Show HN! Not some GitHub issue tracker. Try to insert please and thank you in that post ... it will make it sound rude! It will turn it from Show HN feedback to sounding like a feature request, which it is clearly not...
This is a slight modification of the principle of charity, something I think is incredibly important and underemphasized, especially for online text communication.
Because, that could be the wrong action to take. Could you, Would you, Will you, I want you to, You should, The project is stupid unless you, etc.
Therefore, the author should communicate well enough to be understood.
It costs nothing to be polite.
The best route is probably to clarify that it seems like a good concept, and you think that adding x and y would be the best features to focus on that would make it even better.