Ok, well it's a Dashboard-type style, and it could work just vocals and acoustic, sure. But I agree something is missing from it living up to its full potential, and I believe it's the arrangement and performances. Vocals are rather pitchy, female more so in that regard. Guitar sounds good as it is, sure. Nothing wrong with it, it's a nice sounding acoustic guitar mic'd pretty well. But even that is lacking something for holding attention for this tune. Maybe more top shine?
So, I guess I'm saying that yeah everything was recorded well and sounds ok, it isn't the best combination of sounds for this particular mix and what the song is trying to deliver. It's a really good song and catchy, for sure. I also hear a lack of edits in the vocals, as someone else mentioned. The line "together" and "forever" near the end are really out of tune.
I think recapturing the guitar with an emphasis on top end and re-performing the vocals for pitch corrections would help this mix a ton.
Just my thoughts. Good writing.
Did you know "castlerock" was the made up town in Stand By Me? (taken by Stephen King from Lord of the Flies). Rob Reiner used it for the name Castle Rock Entertainment when the company was formed.