One of the most exciting features on iOS 13, according to rumor, Safari will be always default to desktop version. I am super excited for the change. There are two many websites are defaulting to mobile version on the iPad and it is really annoying. Finally, I don’t need force the browser going to desktop version.
One of other thing i am excited about is the floating windows. Finally, we are no longer being tied with split windows.
If Apple can add Bluetooth mouse support and external storage support, that would be nice.
External storage is the most excited/needed feature for me. The other things you mentioned would be nice but I could live with split window. Desktop versions will only be nice if I can control the scale/zoom like on Mac OS Safari. If I'm still limited to a 1100-point screen in landscape several crucial websites still won't work any better for me.