I can offer an opinion, I wont hurt dans feelings.
I much prefer this design with the bottles on the side.
I dont see much difference in the backs, curved, slightly curved, not really would give that much of a thought, they all look ok to me.
while the wine glass holder looks nice, I dont see why with shelves you need it. The unit is on the floor, the glasses are very low to the reach.
If the stems on the glasses are delicate, people bending down and pulling on the glasses to get them might break a few stems. Im used to my childrens friends grabbing wine glasses. what can I tell you.
and even though Im going to use your wine bottle holding cubes on the side of the unit,(when I build one) I would and will put doors on the center(inset doors, keeping your drawer underneath to hold corkscrew and whatever, I like the drawer idea) to make it look like more like a cabinet, but this is only my opinion. A nice piece of veneer covering door panels would be nice.that is my idea. Your cabinet looks fine, but I go for more of a closed type unit.
oh, I must say also, youre sketchup talent is really tops.