Yep this is constant problem that people wont find spaces. It would be good to have option to force it show all spaces. 

Yeah, I know this is bothersome. My solution was simply to add links to all spaces to a folder in the Chrome bookmarks bar. Looks similar to Recent Spaces and is faster and always works!

We are in the same situation as Jochen, when in a Confluence space, there is no easy way to see all other available Spaces and switch across to a different space.

I appreciate you can click on the "Recent Spaces" dropdown, then navigate to the "All Spaces" option, but those are additional steps/clicks that we don't really want to do when we switch between spaces.

Adding more Recent Spaces to the dropdown would be a good start, but ideally be a quicker way to switch to any of the other spaces.

We are heavy users of confluence and regularly must access more than 10 spaces. There is currently no easy way to have a list with all our required spaces available - configuring and maintaining links in each space's sidebar is really a big hassle. Having to click on spaces, search in the recent spaces list, not finding the desired space, loading the spaces directory and searching there again is also very cumbersome.

Just being able to increase the number of recent spaces would be an easy and suitable solution. Doesn't have to be via UI, a simple advanced key-value option in a config file would be sufficient.