The new fixtures view in the Universes tab is fantastic. Would love to be able to adjust the sliders there as well as in the control pane using the mouse wheel when hovering over the thumb control or perhaps with a modifier key.
I would like to add to this, that's essentially every slider control should be able to be controlled in the same suggested manner Coming from another 3D Viz, that allows such feature, I can say it's really useful... Certainly options like Smoke controls, Fiiture Control Pane (live), Matterial texture RGB sliders, etc...