I'd like to see Off-Topic as well, some things just don't fit elsewhere. General Discussion doesn't really fill that niche of 'if there's nowhere to put this, stick it here'; it actually overshadows nearly everything.
If it were up to me I'd change the Memes & Games sub-community into Off Topic, as those things are by definition not discussion-based material and it could segment that portion of the population in a strange way and/or make moderators' jobs harder. It's really hard to draw lines if two sub-communities are so closely related.
I'd also like to see a sub-community dedicated to viewed content such as streams and YouTube videos. eSports is probably the closest the current platform comes to that, and it's not really accurate. To me the most sensible approach would be to have two sub-communities related to viewed content, one for professional Riot-hosted eSports and the other for the entirety of the near-professional, amateur, and entertainment scenes.
There also needs to be a couple of the really core sub-communities such as Bug Reports, and personally I'd also very much like to see a sub-community for each community initiative that's been done (Honor, the Tribunal, the League system, etc.).
Keep in mind the platform is nowhere near complete! As I understand it, the developers are working to ensure the platform has all necessary central functions (sorting and algorithms, visible moderation, possible terminology changes, etc.) correct and fully operational before bringing in new Sub-Communities.
The goal (from my perspective) is to make sure that there are enough categories to keep things organized and engaging while not dramatically segmenting the playerbase or stifling certain areas (e.g. the concept of General Discussion).
