I think I'd like to see a people and a spaces icon on the left side of the UI, sort of like how you can look at teams. Or from the drop-down menu above messages have one for spaces versus people there. Some sort of option to filter by whether it's a ...

This is awful. If you forget the name of a space it's a lot easier to swim through a list of spaces or people separately than it is to scan through a list of both mixed together. Either offer a filter function or restore the separation. Come on!