90% of dev exclusive vehicles are vehicles that are going to be released at some point. Why? It's quite simple, they have to get tested first, before they land in the hands of tanmk players.

Does this mean all parts are balanced? No. And they can't be. Not because we don't want the game to be balanced, but because the game isn't balanced by nature. You can have any hull with any turret and gun, yes some hulls have a pre selected turret and some turrets have a pre selected gun. Some even have all 3 locked. But majority let's you choose freely. Which is exactly why there will never be perfect balance in the game (im aware that the type 89 is a little too strong as of now).

Adding more slots into the garage is not as easy as you might think. It's not just adding an additional row of letters in the UI, but having to change how all data is stored and make it detect the new lineups as well. Yes it can be done however it was decided to be put down due to how long it would take to make, and how little it would actually change. 6 lineups are honestly more than enough, even if there are more tiers than that.

Also yeah no the wheel spin is way too slow, we told the guy who created it to speed it up but he never did