The V Window is an important feature, not present (AFAIK) in other remote IPAD MIDI controllers, and could be a factor in someone deciding to buy your app, which costs much more than the others.
One wants to try that first though, to see how well it works on one's system.
In your free version, with the V-window being view only, one cannot really get any sense of how it will work as a controller.
I bought a remote display app called Air Display, in which one could use the Ipad as a remote display for the PC or Mac, but also use it as a touchscreen to control the PC or Mac, instead of a mouse.
It (Air Display) worked, in that I could see the PC screen on my Ipad, and could move the mouse cursor with my finger in the Ipad display, but very buggy and laggy, not well at all. (Not saying the program is bad, but it didn't work well with my computer.)
The V Window aspect of V-Control seems similar, in being able to see the computer display (at least as far as other windows of the DAW), and to control them from the Ipad. However, I do not know how that would work on my system, whether it would also be very slow and buggy, as Air Display was. With it being View Only on the free version, one does not really get any sense of how it would work as a controller.
With your full program being so expensive (way more than any other idevice app I have ever heard of!), people will want to know how well an important feature like the V-Window will work on their system? Not only for view, but as a controller.
You write that people should try the free app first, to see how V-control works on their system, but without being able to try the V-Window for control, they are missing an important aspect (of finding out how the app works on their system).
Any chance you can enable being able to control with the v-window (even if time-limited, etc.), in the free version, so that people can test that feature?
By the way, in trying out V-Window (view only) in the free version, even that did not work quite as described in instructions. One could choose either the user manual, or v-window, in v-window one could choose Sonar (my DAW), but from there there was no further choice of plug-in and other Sonar windows, etc. One only saw a duplication on the Ipad of what Sonar looked like (same windows open, same layout) as on the desktop.