Hi.. i think it would be cool, if amarok could calculate the average BPMs of the songs. Maybe skipping the first and last 15 seconds since Intros/Outtros are normally slower.

Then amarok displays the BPM in the playlisteditor and i can create playlists that somehow match speet, since i have very slow and very fast music, the random playlists are... too jumpy.

I dont know if BPMs can be stored as ID3-Tag, but i guess so.
With filters in smart playlists you could do great thinsg, once you know the BPM.

I dont know, how much time it would take to calculate BPM, maybe the BPM-calculation should be done by a script, so you can start it whenever you want, or even an extra programm. Amarok woul just have to display the BPM-Tag.