I was just about to add to the complaints, but after playing around with the UI a bit I discovered (at least in Windows) that if you click into the actual numerical value text-field:
[Up-Arrow] [Down-Arrow] will adjust the value, for exposure, in tenth stop increments. The [Tab] key will move you to the next value text-field, [Shift]+[Tab] to the previous.
What *was* thowing me off previously is that when LR loses focus, it also loses any existing focus on a control - you have to re-select control focus with the mouse.
hth - John