I have seen a few posts in the past suggesting this but wondered where it was at in terms of implementation.
One feature in Photoshop that is incredibly useful is to be able to increment or decrement a value by use of the arrow keys (or scroll wheel).
Not all that useful for processes w/o Real Time Preview but it would be really helpful for those that do to get a given setting just right.
As an example (and there are many others), tweaking the linear mask for an MMT:
