This isn't a problem yet, but looking at how long the lists are starting to get again, I think that the ability to manually adjust the order and grouping of devices in the device creation context menu would be very helpful.
At a minimum a user-defined menu of Favorite Devices or something like that could help save some time searching through the menus. It's the same issue that caused devices to be broken up into submenus to begin with, but I think as we get more REs their management within the menus will become even more important.
In the tool window you can minimize sections and you can visually pick out devices pretty quickly, so it may not suffer from problems very soon, but I primarily right click and create devices. I could change that habit, but as long as it's an option I'd like to see it continue to work well, so please take a look at this issue before it becomes a problem?
Although it's probably been said before, I'd also like to say that I think a shopping cart type system would be nice to have in the RE shop, as well as a wish list!
It's another thing that's not a very big deal now, but when there are several times as many devices in the shop then it'll start to get difficult to remember all of the ones we've had our eyes on.