I find the sort numbers and arrows to be invaluable. I have my main classical music view scheme sorted by Composer, then Work Name, then Artist and then by Track Number. That's pretty complicated so having the visual indication of the sort order is very useful.
When I'm looking for problems with recently imported or ripped files, changing the sort order is one of my main tools. Being able to check the sort order is vital when the track list doesn't look as I expect it to look.
I think that the current mechanism has evolved to be a unique combination of power and accessibility. Most other music player programs don't come close to matching it. JRiver, don't gut it!
Bill