Ok, now that I'm on a computer, here's what I mean about the decorative backplates (and a few other things).
On the gen, the backplate has several holes cut into it (green "1"), this is done on the most recent version of the rep (red "E" and faux jewels red "D"), but the problem is that while those cutouts are technically more gen-like, the rep movement doesn't have gear wheels in the spots where the cutouts are... so there are cutouts that just show through to the back of the un-decorated rep movement. I think on a previous version of this rep there were non-functional decorative wheels that were placed under the backplate, but I assume these were removed to try to make the rep watch thinner. In my opinion, I think the backplate would look better without these faux cutouts. The reason for all of this is because the gen movement has these gears on the crown side of the movement, whereas the rep movement has these drive wheels on the far side from the crown. I think these cutouts also look really strange because they actually DON'T line-up with one of the gears in the winding mechanism (red "C" on the watch with the blue strap).
Next is the main spring barrel. It looks like the updated rep now has a gen-like look. This is good. The older version (red "A") looks very different from gen (green "2").
I like the divided backplate with the backplate for the movement and a separated bridge for the tourbillon (red "F").
The differences between the three reps in terms of the manual winding gears is interesting (red "C"). I'm guessing that the thinnest version was the oldest (bottom left) since it's backplate didn't even cover the winding gears, whereas on subsequent versions the backplate sits on top of these gears, making the watch thicker. This also shows in the way the backplate on the bottom left version needs to have cutouts (red "B") for where the movement is anchored to the case; the other rep versions have this mechanism covered by the backplate.