Hi Artaher,
if you do a search you will see that we had this discussion about Yamaha styles several times in the past.
When I auditioned different KB's in the past I was very intrigued by some of the style patterns and their variations.
Even though I liked a lot of the styles, I couldn't come up with any songs in my repertoir that the styles would fit.
As drdalet mentioned the Yamaha styles leave enough room for my own playing and are not getting in my way.
By using different variations, fill in's, breaks multipads etc. and of course my right hand playing, I bring the music to live.
Plus I am a singer therefore I don't want the KB to take over. In my case it is supposed to back me up.
Several people in the past, that use Yamaha KB's mentioned similar things.
However I agree with you that it would be nice to have more variation in the strum pattern to give it more a live feel.
As a matter of of fact, Yamaha used to have a button on their older models that would do that. You push it and the strumming changed.
Different strokes for different folks.
What a great concept. Imagine all KB's would do the same thing.

How boring: "A" we all have different needs as we can see from this discussion and "B" we could close the SZ because we wouldn't have this discussion.

Eric