Except for maybe the canopy/heatshield of the V1 VF-1, there are no other parts that needs to be swapped to ensure transformation, unlike the 1/100 VF-25s. You could still transform the V1 VF-1 without the presence of the the filler peg for the nose and arm panels, and even without the canoppy/heatshield. But you can do the same with the 1/100 VF-25s.
It wasn't perfect transformation, but you did not need to really swap essential parts just to transform
For the VF-19, I'm pretty sure it is perfect transformation, but they might bundle some optional accessories to fill up the upper calves of the VF-19 in battroid mode. However, I think it is pretty much fine as it and I really don't see the need for any fillers. I'm sure the the Hi metal VF-19 owners would think the same for their toys as well.
Really hope that this can be released by end November this year so that each of us can buy ourselves a nice Christmas present.