Yep, I'd have to agree. The difficulty is there's no real plot outside of the romance or internal issue, so lots of pining. It works better if there is an external issue or plot. Or problem. Something that's keeping them apart, besides - I don't know if she/he/them likes me or not.

I don't mind pining as long as it doesn't cross-over into whining. Which unfortunately it often does.
I need banter, preferably witty banter, and not a whole lot of navel-gazing thinking. I'd rather not know what they are thinking - particularly when it can be done with dialogue.

You're right about some mysteries - they can get repetitive too. It's the internal dialogue that is the culprit. And a lot of writers suck at dialogue and rely on it instead of dialogue. I'd prefer the dialogue.