What a gorgeous dress! It's lovely on you. Simple, elegant, dignified yet alluring. I love the sleeve detail -- covered without being hot. And though I can't really make out the capey thing on my laptop, it sounds fantastic and a bit floaty.
So...do you need it taken up at the shoulder because it is too long in the torso (i.e. waist in wrong place)? I sometimes run into this. If so, and they are able to do the alteration, I think it will help with the key issues that I see (or maybe miss-see; as I said, I'm on a laptop.)
Anyway...whenever I need to do this, I find that the dress comes up *just enough* in the neckline .Here, it looks just a touch low to me, not because you don't look good in an open V but because this one is a bit off proportionately. And it also raises the length of the dress by an inch or so. I like the below knee length on you but because of the depth and width of the open neck the proportion looks a bit off to me -- heels would help for sure, balancing the bare skin bits, and of course it may not be as "off" as it appears -- it's hard to judge due to camera angle -- but I do think bringing it up would create more vertical balance on your frame and show your figure to advantage. Let us know what happens!