Completely random questions? They relate to the character's personality very well, and it gives you more heart to hearts with them. Also you can gift the collectables to them for further affinity. You wont max out affinity in one playthrough for everyone though.
Eventually you don't need monado enchant because you can acquire weapons that allows everyone to hit mechon.
I agree with your points, though they weren't as big of an impact to me. I saw what they were going for, and it's not perfectly implemented you can get around that in multiple ways and still derive enjoyment from it.
To be honest, I like they included the elements you called "half baked" rather than not at all, because those are some of the things I want in a game, though yes there's room for improvement in everything. However, I thought it gave the best bang for your buck and experience in an rpg unlike any I've played.