I know you’re considering a command-palette type feature. For the purpose of finding and navigating spaces, perhaps making the space dialog more keyboard accessible would be a quicker solution in the interim? It’s almost there already: after clicking on the menu, I hit Tab twice, which takes me to the search field. I can then search for my spaces and then hit Tab or Down for the results, Enter to navigate.
So being able to open the space dialog with the keyboard, and focusing on the space search, would go a long way to make it easy to switch between spaces without leaving the keyboard.