Thank you for explaining. There is a bit more plastic in the v7 in two places. The main body has channels to keep the motor wires tidy and the stand has a wider base to aid stability. It is nice to hear that the Pi camera v1.3 support that one of our users added is useful for you.
It sounds as though you are not planning to add motors. We have a version of v7 for manual operation. It takes away the cable channels and motor lugs and is much neater for manual use. In that version we go a stage further to lower cost by using a webcam instead of the Pi camera and a Pi. You can equally use the Pi camera version of the basic optics and our software for better image quality. The very minimal stand designed for that version does not have a place for a Pi, but you can use other bases. We introduced the electronics drawer to make access easier and to keep the microscope screwed to the stand. We found with version 6 that when people had to unscrew the main body to access the electronics, they often then did not screw it back together afterwards. If you do not use the motors, the drawer is less necessary. A short stand would hold the Pi and would save plastic and printing time. I am pretty sure that it would actually fit in the no pi stand (the white stand in the first image on the linked thread)
What do we think is made better in v7? The stage and illumination are made much more robust and more user friendly. The stage top now uses embedded nuts, rather than threading the sample clips into the plastic. Stripping those plastic threads is a failure mode that would require a complete new main body. The illumination on v6 is not lockable and was very prone to being knocked out of position. The v7 illuminaton has a locking dovetail. It is also narrower, which allows the sample clips on the stage to sit on the same side as the illumination, making far better access for inserting a slide. The v7 illumination is completely compatible with the v6 body if you want to.
Other changes are more in the internal structure, improving printing in a couple of places. V7 has a reduced number of different screws - all M3 screws are now 10mm length, M2 and M2.5 machine screws are replaced with a single type of self-tapping screws. The band insertion tool is also made so that it is stronger, which makes it easier to use. Together with the slight change to the design of the feet this should really help in assembling 300 actuators in your project! Again, the new tool and the new feet should be compatible with v6 if needed.