The switch to WordPress went far from optimal. I guess one problem was solved, but at the same time many more created. Maybe it’s the specific theme that is used here. Maybe WordPress more generally is not the best choice for web applications like this one – centered around many users interacting with one another (some sort of forum), sharing content (streamlined up- and download procedure) and commenting / rating submitted content?
Additionally, there is also a need for a more flexible filtering / ranking / querying capacity, to allow a better overview and search function.
Wordpress was originally designed with individual blogs in mind, basically one author that also did the whole administration part. At best visitor’s could comment a blog entry, but that was it as far as interaction goes. But here we have a website for a collaborative venture, which has other requirements.
It would certainly take a specialist in information architecture or a web (mainly backend) specialist to redesign this into a more straightforward web application.
The specific improvement needs summarised:
more streamlined submission process
more flexible submission process (one that allows additional submissions of eg patches in more formats by the author autonomously, once his initial submission got accepted)
cut the need for login to download
better search / filtering / ranking options
ability to comment on individual instruments (I believe not currently working?)