Ok - a little sunshine on this shady (crowdy?) topic:
I have Sample Tank XL and Sinc Synth 2. I actually liked a number of things about both of these libraries, especially at the time over the other options I had, but the interfaces, especially over time with larger real estate, dual monitors, etc.
That said, I was really happy when they released the Free version with the option to import all the old libraries. So now I have the 64 bit plugin that has all of my old sounds in it, some new engine capabilities, and (shallowly, most importantly) the mouse wheel works. So as inefficient as the interface still is, being too small and I suppose a tree view as pointed out above, being able to scroll with the wheel is a tremendous improvement!
Certainly wouldn't expect to have to wait for 10 years for a new somewhat better interface with mouse wheel support. But for free (without the new sound libraries), I'll take it!