Well, let me try and explain it from a developer point of view, bear in mind I'm not the coder of the game, Panda is, but I'm a coder as well in another game.
Changing engines right now would slow us down a lot, the game is done and shipped, it will receive more content but the core of it is already there, changing it to renpy for example would consist in re-importing everything, setting up branches, setting up renders, portraits, emotions, text and everything else... do you follow? It took us 18 months to get where we are, if we needed to redo everything instead of adding new content, it would take us a long time before any of you guys saw any new content.
So when Panda says that talking about the engine is useless, it's in the objective of saying we won't change it, it's too late for that, but we can improve on it to get it on par of any other option available out there, so feedback is useful, but not one just saying change to renpy.
Panda is already working on increasing text speed, that's because of the feedback from you guys, and that
is useful, so if you got complaints of what we can do to improve on what we have, please let us know, that we can and will do, but changing engines is completely out of question for Midnight Ride.