Yes to ALL of these!
The single most-important one to me right now is to be able to set which wheel I start on when first opening the radial menu.
My preference would be to start in the middle, go left to the wheels I configured for increasingly higher levels of spells, or go right for more niche combat options. Instead, it seems to always start me on the left-most wheel which wastes a lot of time.
Also, it would be nice to have nested wheel options. For instance, one option to open a sub-wheel for cantrips, another for 1st level spells, one for melee attack options, another for ranged attack options, consumable items, etc...
Lastly, in multiplayer it we need a way to be able to edit our radial menus out-of-game so that we aren't wasting our friends' time by requiring the host to be online.
And yes, I still don't know how to trigger reactions either. I have Feather Fall prepared and figured I'd get a prompt when a party member within range jumped off a tall cliff. NOPE! Instead they cratered and I'm wondering if I basically wasted one of my Bard slots. :-\