I've not seen a comparisson chart for all versions of PrE. It would be useful, and might exist somewhere. Adobe did have similar for all versions of Photoshop, but that was as close as I've ever been able to come.
Now, I had to do similar for Premiere and Premiere Pro, when I inherited two older Projects, started on earlier versions of Pr (6.0 and 6.5), and I had to find all the differences between those older programs and PrPro 1.0 and then PrPro 2.0, the version that I was going to be editing in.
The best that I could do was find old reivews of each "newer" program and look at the feature lists for each vs the version that it replaced. I had to do this for every iteration of the program and sort of compile my own chart. I was looking for changes that would possibly affect how these older Projects would Import/Open in my version of PrPro, so I had to "read between the lines" a great deal. I did not compile a chart, per se, as I was only interested in problems that I might encounter, as I worked on these old Projects and did not care for a full feature listing (unless I though that it would impact my workflow).
Later, I did do a chart comparing PrE 4 to PrPro 2.0, but it was neither 100% complete (I only compared the features that I used, and not the full compliment), nor is it still around, as of the last Adobe forum redo.
In your case, this would be a review of PrE 3, a review of PrE 4, PrE 7 and finally one for PrE 8.
Also, some reviewers are better, and more detailed, than are others, so you will need to do a bit of reading. If you can find a good reviewer, who goes into feature details, you might be able to trace their reports for each version.
Good luck, and if you DO find a comparisson chart, please post a link to it.
I had forgotten about those. In the "old days," I think that there was also a list of features for PrE 4, but it's now gone after the forum changeover. I wonder if any such articles are still up on Muvipix?