Amarok has become my favourite music player for Linux and in fact for any OS. However, here are some features I would like to see in future.

1. In Collection view double left click on artist/album would REPLCACE the current files in playlist with the new ones under selected artist/album. New files would also start playing right away (without need tp press stop and then play like Amarok does now, if you right click -> load those new files)  I think this would be better than adding new songs to the end of the playlist. Some might prefer the current way to do this but maybe this could be an option also... ?

2. Double left clicking artist/album in Collection view would also send you to Context view at the same time when files start playing. Again, this could be an option you could turn off.

Finally, mute button would be handy. I know you can right click on volume bar and choose 0% but it's not exactly the same 

How about just clicking Pause?

You can set a global shortcut for mute.