Dress #1 is beautiful to me, and if it were up to me I wouldn't change a thing :). Maybe what's bothering you is the sleeve trim and the waist trim are both at the same height? I can see how it might look like a black horizontal line if you're standing in front of a mirror with your arms down.
Rolling your sleeves down (assuming you can do that) or adding a belt both sound like fun experiments to try. If you're worried about the belt slipping, perhaps you can throw some fashion tape at the problem?