It would be nice if the hooks were less noticeable. I think the shiny finish draws too much attention to the hooks. If you were able to find a more muted finish, and maybe just used a pin (instead of a hook) to keep the blade open, I think you would reduce the visual clutter and better guide the eye towards the razors, which is what you want.
It would be cool if you could incorporate some sort of lighting around the perimeter of the box. Maybe something like a strip of warm balanced LED's running around the inside edge. I don't know what's available, but that would be a cool option.
If I were to buy a case like this, I would prefer a simple, tasteful knob instead of the handle. Or if you used a handle, perhaps a smaller, subtler one, that compliments the lines of the box. I feel that the curved handle you're using now feels a bit mismatched with the straight lines of the box and may be slightly too large.
I agree that if the box were made for the bathroom, I would want maximum airflow/ventilation vs. weather sealing. Unless you you started with a dry case won't be opening the case at all, you'd want to give the moisture every chance to vent out. If you sealed in just a slight bit of moisture, I would think your blades would start oxidizing or rusting.
Looks fantastic. Wish you had one for DE's as well.
I agree with one other post in that the hooks stand out from the background, I think it may look a bit more sleek if the hooks were the same color as the background. That way they would sort of disappear visually.
Lighting would also be great but isn't a deal breaker.
I would definitely buy something like this if I had straight razors.
Very nice sir! I'm no Bob Vila, but to my eye that is a very nice display case. The rubber spray sounds like a nice idea, but if it didn't work out for you, I think its still a beauty.