I agree with Maxal here. At least, in some of it. I didn't mind David, but he definitely was not one of my favorite characters. Adolin, for sure is a better character, IMO. The weapons skill makes sense for both, I'd say. The thing about David's info gathering is a bit stretched. Yes, he spent a lot of time doing it, but how? I'm not sure how he paid for all those photos and stories as a factory worker. That's what I've never understood.
And I'll also agree about the relationships aspect. David is much more in an infatuation stage, but he is growing and falling in love. He does put Megan first, even though it's really just a crush, which isn't an awful thing, I understand that, but it's not all that great. Adolin understands that his duty is more important.