Hey - I agree that the arrangement is too sparse, but despite that, (or maybe because of it?) I actually think the drums are way too busy for this.
Agreed on the vocals. You captured them well and when your pitch is on they sound good, but it seemed like you were struggling to find the notes at times.
You've got some nice tones and there's good clarity and separation in the mix, but personally, I'd recommend simplifying the drums, retracking the vocals and adding more melodic elements to fill this thing out a little more.