Arg. It's annoying to spend 20 minutes crafting a reply and posting images only to discover one's session has timed out and you just lost everything by clicking "Submit". Swear to God, if I ever get access to a time machine, Tim Berners-Lee, me, and a baseball bat with a big spike sticking out of the end are going to have a real heart-to-heart about this whole "stateless" thing.
Anyway...other cases with "stealthed" optical drive doors seem to manage without the gap; Lian Li comes to mind, but even very inexpensive cases like some NZXT models do it better than this.
My grip with the "drive present" button wires is, I guess, not so much with their thinness (you're right, they're not THAT thin), but rather the fact that you have to thread SATA power and interface cables around or through them during a build.
My Level 10 is sitting on a desk. Seen straight on, the USB indicators are very dim. This photo actually makes them look a lot brighter than they are; in real life, they're almost invisible:
Looking from above (as when the case is sitting on the floor) it's a lot better:
If I grasp a drive caddy and tug on it with the case locked, it will move a couple of millimeters, enough to disengage the "drive present" switch:
A push on the caddy will restore the light:
I'm pretty sure your case will do the same. Give it a try. You can see the slack in the latching mechanism with the back off.
I've been experimenting with plexi side panels and internal lighting, but as yet haven't come up with anything I'm completely happy with. For instance, I don't see any way to keep the lower light bar out of sight:
Overall, I'm happy with the case, but think that a little more thought and a few more $ would have made it better. HP's old "Blackbird" case is a good example of an uber-high-end case where the designers did sweat the details in a way that Thermaltake didn't. The Level 10, though, does at least have 8 slots, which the HP does not. Surprisingly few reviews mention this.