I especially like the option to auto move full screen windows to their own workspace

That is a useful option. Some time ago I played with another extension which handled that and I liked the work flow. You could name the app in the Extensions app settings for it, and allocate a workspace number. Too bad it often broke and I got tired of that. If this were an option in COSMIC I’d use it for sure.

This is a really neat concept. I love that they’re recognizing the tradeoffs of both tiling and floating window managers and imagining a better way.

I think the mosaic idea is interesting and has a lot of potential. I agree with their self-assessment that it’s success depends greatly on the simplicity and utility of the window preferred size API, and how willing/able app developers are to adopt it. This is unfortunately yet another place where the fragmentation of the Linux ecosystem shows it downsides.

Nonetheless, I’m really hopeful about this. I would love to see a future where mosaic window management becomes ubiquitous. But really I’d be happy as long as my desktop supports configurable workspaces.