I can see why you are doing this and I do think the idea has merits but in the current execution has issues. I would say it has gone live a bit too early as right now there is basically no gain with this and just a lot of headache for users.
Here is a few observations I have made so far:
For a start you are using default textures for the models not regional textures so the advantage of picture and model being identical in appearance has not yet been achieved.
It actually makes it far, far worse in the case of the models I have made as you now got all tanks in basic green instead of an assortment of default or regional textures used on the UGBITS. The small scale just makes it even worse.
I also fear at this small scale camouflage and the like will blur and make identifying units harder than it was with the UGBITS icons.
Edit: Here is a few illustrations of what I mean. All vehicles are roughly 64 pixels size (the lower 9 exactly 64 pixels wide)
I do not find it exactly easy to identify what model of tank each of these vehicles are and I know them in great detail. At a casual glance it is probably going to be more difficult than with the UGBITS icons where they used a variety of different textures.
On top of bridges powerplants and the like that has icons representing what they are now also far harder to identify by their icon/model alone.
Unit production still uses the old icons.
I know you have mentioned model scale and that really is an issue. Look at aircraft carriers for the perfect example. Like half the model is visible in the icon window. Aircraft have some of the same issues.
Buildings also needs to be re-centred as right now many of them are small blobs in the lower part of the window.
On the other extreme great war warships are basically small blobs that are impossible to identify.
Texture appear to be scaled in the unit preview. This does in some cases result in edge bleeding. The perfect example is some of the warship models I have made.
Likewise as mentioned you got grey on grey now. Case in point is the default texture for the F-15 model I made. It is basically invisible on that background. Some of the old 2020 aircraft have the same problem. I would say that is a significant issue that outweigh any advantages of units being in region specific textures (especially with the potential issues mentioned above).
I am sorry but I am not going to spend a few hundred hours fixing those texture colour issues. Part of the problem is a lot of aircraft and warships in particular use a similar colour and the goal of what I do at least is to try and make accurate models. Straying far enough from the background to make them stand out really will compromise that and that is a sacrifice I will not make.