There's nothing wrong with VI. I had one and loved it. The VII is just better. Way more display options with missiles and BD parts and of course the repulser hands. It is bulkier and sturdier. It has better back flaps that lay flat. There are no wonky hip flares. All the BD pieces fit properly. The neck articulation actually exists now. There really isnt anything the VI brings that the VII doesnt do better other than possibly the face plate, but even then, people complained that the VI helmet was too small and skinny.
So you already have one and you have a few more on the way? They are all nice figures but you really must like the Mark VII.