Did they also want the text and thumbnails to be invisible against the row highlight if the row wasn't 100% exposed and the arrow key to only occasionally work? If those are the result of settings I can change, please tell me because the latter is driving me banaynays.

Hmm - I am unable to relate to either thing you said. For the visibility problem, can you show an example? As for the arrows, I have never found them not to work as I expect. Are you talking about changing the selected item or folder with arrows or something else?

I am. As I've just started Poser up again, I can't reproduce the problem but over time the scroll starts to look like this at the bottom if the selected item is half under the scroll:Usually at this point, the arrow keys do not change the selection or expand/collapse folders. I can click around a bit and sometimes it returns, but it's not guaranteed to work. This is the case on my rMBP regardless of whether I'm using the built-in kb or a USB external.

Also, the scroll speed of this widget using the trackpad is ridiculous. If I have a mouse, I can use the wheel or drag the nearly invisible scrubber (not your fault, it's the default UI for poser), but just two-finger scrolling with the trackpad goes incredibly fast no matter what setting I have for the trackpad's actual tracking. rMBP internal trackpad, two finger scrolling, USB internal connection. Fine tuning settings with BetterTouchTool has no effect. 

Is this somehow related? http://labs.byhook.com/2010/04/09/flash-mouse-wheel-support/

Again, if not my apologies.