The improvement would come from Vince taking the tag - simple yes, but has had massive ramifications for players in the past who have been allowed to score more freely.
I also have never been a fan of the "too many good mids" idea of "too many players" - look at Geelong (ABCS, Enright, SJ, Chapman), Saint Kilda (Goddard, Hayes, Montagna, Riewoldt, Dal Santo, etc) and even collingwood (Didak, Swan, Pendles, Leon). Theres no reason why a potentially top 4 team can't have multiple high scorers who share the ball around.
Its not that there is too many midfielders, it's just that they take so many routes to goal. Geelong have a lot of gun midfielders but they all usually touch the ball moving forward because they share it so much whereas Adelaide go forward through anyone. That's just what I observed last year.
Looking at last year's Fantasy Freako from Rd21 Thompson had averaged 83% TOG for the year with Vince 77%. In a team that doesnt depend on them outside of ball ups as much as midfielders at other clubs, I think you want it to be more.
I think Brisbane, Hawthorn and the Bulldogs' midfielders are similar to Adelaide's in that they dont have to go through certain ones.
Luke Power (90% TOG), Sewell (88%), Mitchell (94%) although they do like to go through him and Daniel Cross (88%) are examples of where I would like Thompson's TOG to be.
Not as important for Vince if he is to be tagged this year but yeah, you have a good case that he will rise slightly but I dont think more than 5ppg.
I would much rather pay 10k more and get say Selwood, Pendlebury or Mitchell.