A clock in a computer can make the computer a clock, but it doesn't make the clock a computer...

An arranger is an amalgam of components, but a drum machine is not an arranger, an mp3 player is not an arranger. They are merely components of an arranger (or at least, some arrangers My G70 never has had mp3 playback or recording).

For me, at least, it is the 'combination' of different things that makes an arranger... Yes, it needs chord recognition (without it, it is an old school WS), yes, it needs styles (without them, how useful is it, or why is it not called a WS?), yes, it needs a well integrated sound set (or patch selection live is a nightmare), yes, it needs an easy to operate OS (or your live show is a nightmare, again), and yes, it needs to be FUN!

OK, it doesn't HAVE to have that last one, but who wants to play something that ISN'T ?