There is one feature that i would really like if it's not too hard to implement. The ability to specify a playlist to send the files to on double-click or middle-click.This would basically allow someone to easily send tracks on a predifined playlist that's reserved for playing tracks and not use the library selection playlist to actually play tracks as it tends to become messy when you then select other tracks to eg. tag them.
Just go to prefrences, disable any action for single click, and for the rest use "add/send to selection playlist"
Does anyone have a problem with having album cover to show up on several albums?
It's simple: The two panes doesn't belong to one layout! you have two independent facets!A new facets layout starts with three panes - you can add more if you need or you can remove some panes to have less or just one. You did the latter probably to achieve a special design but you just can have the panes vertically or horizontally orientated.