It should be possible to adjust the radius of Soft selection (Proportional editing) while not transforming.
Right now you have to start moving, rotating or scaling your selection before you can increase or decrease the radius of influence on the soft selection. You have to hold down translate and then <kbd>PGUP</kbd> or <kbd>PGDOWN</kbd> or scroll to change the radius. When using a Wacom tablet it is near impossible to hold the cursor perfectly still while doing this so you end up making unwanted transformations and having to undo them just to change the influence size. This is especially problematic when the radius is very wide and you end up transforming everything around the selection until you've lowered the radius. If you could adjust this while not transforming it would solve the problem.
NOTE: current radius should also be visible on the cursor when not transforming (any time soft selection is active)