There are always restraints and compromises in music. If I play solo piano I am free to do anything, change tempo, change key, repeat sections etc etc. But it is inherently constrained - one instrument only 10 fingers! So you choose what you play appropriately.
But as soon as I involve other people other restraints and compromises appear. Playing in a large group needs full written score to avoid chaos. Then it can be a very elaborate arrangement, but the freedoms disappear, because now my job is to play exactly what is written, no deviation.
Playing in small bands is in the middle - you get some freedom, but can be much less elaborate.
In most ways the arranger is no different. I can make a multi track midi, play along with it and have a very elaborate arrangement, but cannot deviate. And it is a lot of work to prepare. Or I can just sit down, use a generic style and have quite a bit of freedom, but cannot exactly reproduce an elaborate arrangement, and so the accompaniment can be a bit repetitive.
If you make more elaborate styles, then some of the freedom also disappears. 8 bar styles for example might offer more room for an elaborate arrangement, but it introduces some other constraints and might work great for a custom style, but not be very generic, which is why Yamaha largely avoid them. Having more variations available is somewhat in the middle - it is more work and obviously more cost for the commercial suppliers, but does remain fairly flexible because you don't have to use them all. But there are already ways to get similar results, so that becomes pretty much a viability question.
When I played in small live bands, it works more like a style than people here seem to think. The accompaniment is fairly repetitive, and the main thing you think about is that the accompaniment is good enough not to distract - ie doesn't mess things up for the vocalist or lead instrument - which is what people really hear. In a good band, everyone is competent enough to play their part but not get in the way. And the accompaniment might pay lip service to well known recordings of the song without trying to become a carbon copy.
When I sit down at the arranger, it seems very much the same to me as the small band. As long as the style is appropriate and well made, it will sound reasonable, and what really matters is how well I play my lead - things like ; is the overall arrangement nice, is it a good song, have I added some individual touches like chord alterations or extensions, is it interesting. My enjoyment and satisfaction comes mainly from what I play, not what the 'machine' plays, as long as it doesn't spoil what I play.
When a new arranger is on the cards there are lots of posts about how to make the voices better, styles better, more easily editable, more realistic. For some people that is important, especially if you get paid to play and want to produce the illusion of a big sound from a OMB, but not use backing tracks.
But the unfortunate truth for most of us is that the voices, styles etc on the arranger are already pretty decent and to sound significantly better you mostly need to play better, and worry less about styles and whether the piano voice is sampled at a high enough rate.
Mike
