I like the idea of replacing or adding to the rating system. How about adding a count for the amount of times a tab is favourited? So that the tabs with the most favourites will show up under the top tabs? I know that some users probably don’t use the favourite feature, but displaying the number of times favourited along with a tab might encourage people to use it more. Also it might be a good idea to split the top tabs into 2 sections Fingerstyle and ‘Electric’ guitar so that they don’t have to compete with each other.
For the requests and submissions it would be great to see which tabs still need to be submitted or fulfilled instead of having to go into each post to check. I know this other website that uses Discourse for its forums, and they have a solution feature where forum posts are displayed with a checkmark when a solution has been found.
Also, not that important but what about an option to delete comments on the main site? I joined this site 10 years ago when I was 15 and I die a little inside every time I come across an old comment of mine lol.