In my opinion, it is currently hard to consider Funkwhale a full-fledged music streaming service or social platform. Right now it's at an intermediate stage between a personal music server and a full-fledged streaming service. This means is that it has a vast amount of room to grow.
Here are a few issues and feature absences I have compiled after a short time using Funkwhale (many have also been noted by other community members). Hopefully this list can be of some use to developers and contributors.
A Quiet Social Platform
Funkwhale's first objective was to serve as a music server, so currently it feels more like a silent archive than a bustling public space. There is not much that gives a new user a sense of life and activity when they visit an instance for the first time, with there being no trending page and nothing else to indicate what other users have been doing. The closest thing currently available is the "recently uploaded" section, which doesn't even tell the viewer when the content was uploaded, only when it was originally created. Since most uploads are older music taken from elsewhere, the music could have been uploaded years or minutes ago and the user wouldn't be able to tell the difference.
There should be a like or favorite button to allow users to show love for a track. The like count doesn't need to be displayed everywhere and turned into a competitive status tracker like in Audius. Listens should also be counted to determine what is generally popular. Using this data, there should be some sort of trending page (possibly the upcoming reorganization of the "browse" page) that gives you a vague idea of what other people are listening to and interacting with. It doesn't need to be as focused on numbers, rankings and status as other platforms. It could be just a more casual collection of tracks with a good amount of recent listens and interactions sorted by genre.
Another part of the solution is user commentary. Other forum members have noted the absence of this. If funkwhale is meant to be a truly social platform, users should be able to talk to each other in their pods. They should be able to make posts or have discussions on instances, or embed posts and discussions from other fediverse services within them, so that all users of the instance can see and participate. Track comments could be a good addition, but it depends on what kind of atmosphere you are aiming for with the platform.
Account Creation Confusion
There is no good instance for new, casual listeners to create an account on. It seems like some channels and many features one would expect from a streaming service are only accessible to users with accounts (which makes sense), but the largest instance with the most content (open.audio) only allows artists and creators to register. This would be fine if its content was federated to open servers, but it isn't. I don't know if this is just an open.audio issue, but it strikes me as bizarre.
Two approaches can be taken here. The first is to simply federate the channels of open.audio, allowing accounts on smaller instances to access them (it appears that this is being implemented through instance following). The second is to create a distinction between listener and artist accounts, and then allow listener accounts to be freely created. Ultimately this hinges on the desired structure of the platform. The first solution (which is currently being pursued) entails a structure in which large, distinct creator pods create music for a wider network of smaller user pods. Whether this is preferable should be decided by the developers and community.
Impeded Music Discovery
In general, music is not sorted as you would expect it to be. When browsing through any of the pages, content of all genres, languages, time periods and quality levels are mixed together randomly. Genres are currently implemented through metadata tags, but a huge amount of music is completely untagged. Sometimes music will have tags in different languages. Some smaller genres will be split across multiple similar tags, each leading to maybe one album and a couple channels. There's also no easy way to discern music posted by artists who are participating on the platform from music uploaded by other people in libraries. Channels that seemingly require an account to view once you click on them are also strewn throughout, which is a bit annoying on instances where accounts are restricted. All of this works together to severely inhibit music discovery for the average user.
Many important remedies are listed in this issue. However, I would also suggest creating a strict global genre system alongside the tag system, since it doesn't seem like metadata is a very reliable way of sorting music (especially when taking into account different languages). In this theoretical system, all new music must be assigned to a broad genre (e.g. electronic, hip hop, jazz, rock). Each genre should have optional predefined subgenres. A more reliable, consistent genre system would be extremely helpful in creating a more relevant trending/browsing page. I also believe that original music from artist-run channels should generally be considered higher priority than music from libraries.
Thank you for taking the time to read through this huge essay, and I hope it can be helpful in some capacity. Please respond with any of your own ideas or corrections if I misunderstood something.