My main gripe with most Linux DEs is inconsistent UI and lacking app ecosystem. For now, only GNOME is addressing these issues with GNOME Circle (I already like and use apps like Spot, Paper, Amberol, Warp, and others) while having a good-looking UI. Also, GNOME is the only DE with usable trackpad gestures. If COSMIC is going to use GTK4 for UI and implement trackpad gestures similar to these found in macOS or GNOME, it would be probably my main DE.