Buildable vehicles seems like such a great idea, but there's so many problems with it that seem like easy fixes, yet nobody has bothered to deal with them.
Such as the fact that there is no way to save your vehicle along with a build so it loads with it, or even respawns with the chassis. Everytime the vehicle respawns or the save is reloaded the vehicle has to be reloaded via command
There are no good custom chassis yet, the only set of chassis other than the default don't work well because iirc they have a handful of bugs.
Transparent nodes look horrible cannot do

And there are all sorts of things that could be added to just make the mod all around better.
Like maybe a blue hammer or something that's made specifically for breaking bricks on a buildable vehicle. Bad example, but still, there's a lot that can be done with this. It just seems like this is a great idea that has been proven to work, and then forgotten