Is there any way for an owner or shop to turn off the spring central detent on the throttle control? I'd just like it to stay where I put it. This would free up my hand to pitch the camera smoothly as the copter is ascending or descending.

I think you are looking at this the wrong way ...

You should be asking for the feature that we are waiting for called "autonomous flight"!

Alan,

If this was to be set on the controller the stick would stay in the last position say above the neutral and this would result in the aircraft continuing to climb at that ascent rate.  This function is normally controlled with a spring in the back of the controller.

I use a Futaba controller for my Phantom 2 and this is how it is set up.  If you want neutral you have to put it into the neutral position manually.  This can be good if you want to climb at a very smooth controlled ascent.  It can give you some good smooth shots, e.g. one notch up from neutral will climb very slowly.

Just unsure if it can be done on the Inspire platform/ controller.

Yes, I prefer how it works on my Futaba.  As for the best feature for me that I could request in the firmware... a way to click on a spot on the screen and have the camera lock on that spot as you move in any way.... with a quick and smooth way to disengage.