Well, Scott, as you are definitely well aware, a REAL bass line LEADS the chords, and an arranger bass line FOLLOWS the chords. This, to me, is one of the biggest 'dead giveaways' that you are using an arranger, and contributes a LOT to the 'fake' sound.

It's been a very long time since I did bass pedals, but I still do about 60% or so of our show playing LH bass simply because I can't stand the bass line the arranger chooses for me.

For me, music is very much a 'dual melody' approach. There's the melody at the top, and there's the melody at the bottom, and then in between is the rhythm and chords. Kind of like 'figured bass' from Baroque music. Lose the melody at the bottom, and you change the entire 'flavor' of a tune.

A really good exercise for anyone that wants to learn more about the importance of a bass line is to put your arranger into Full Piano Mode, but turn OFF the bass part. Split the keyboard, put your MBS part on, and play a tune. Just sing the melody, play chords in the RH. But PLAY a bass line.

You will notice you almost can't help walking bass lines UP to a chord change (or down, whatever!). The bass player ALWAYS knows what chord is next, and shapes his line to point to it before it arrives. The poor arranger bass line NEVER knows what the next chord is going to be UNTIL you play it! So forget 'leading' up to it... It just jumps there with no voice leading. Once you start to hear this, it is hard to be satisfied with the machine bass.