Hey Gareth, great write up! It’s really cool that you’ve taken the time to write down all your initial impressions so meticulously, and it’s really awesome that you have such a nice impression so far.
I’m sure the guys at HQ will read over everything you’ve written, and I can tell you that none of it will fall on deaf ears.
We all know that Audio makes for a particular marketplace here, compared to some of the other Envato sites. So several of your points, notably the commission incrementation issue, have been brought up a couple times. Overall though, I can tell you that so many little improvements have gradually come about over the last couple of years, especially in the last few months. Envato runs on iterative improvements, So I think it’s a sure bet that things will keep improving. 
Anyway, best success here with us at AJ, market your music well, and I for one will definitely look forward to reading your next review!