First and foremost, the dimensions will be different and more correct. The V3 lowers, for example have some features a little distorted (walls are too thick, magwell bottom and trigger guard extend too far down, and the pivot pin is too big).
I haven't actually test built anything yet so I don't know what's possible and what's not, but modeling the hammer would also be nice.
As for the upper, same story, I need to correct some things to make it more correct.
Now here comes the main challenge: The V1 and 2 uppers were a mess, because the outside walls are supposed to be curved and that tends to get sloppy (every time you build it, it might come out a little different, and always a little crooked). On the V3 I solved that problem by making the core of the upper a single rectangular box, where the curved walls are just exterior components. The problem is this restricts the inside space, limiting the size of the bolt carrier and forcing it to be unrealistically narrow. Expanding the bolt carrier requires making (thinner) curved interior walls. How to do this while still being able to control the fit of the final product? I have a few ideas, but I don't know what will actually work.