Hello BogdanH,
In my personal opinion, Ketron's audio styles give the most realistic accompaniment sound and the best I have ever heard. But we must keep in mind that we're talking about a brand that has no sub 4000€ keyboard -Ketron chose audio styles path to separate itself from the rest.
As you mentioned, we have here both positive and negative points. Yamaha is indeed strong in terms of cost-benefit, with excellent voices, especially the acoustic ones, an advantage over Ketron. But you must agree with me that having limitations of such a feature available only in top and more expensive keyboards, and realizing that Yamaha did not advance in the project, is, at the very least, disappointing. It shouldn't have started in the first place!
It's not only people with high purchasing power who will buy a keyboard like Tyros and Genos to play at home and relax. There are also those who want a true arranger on stage, who listen more than the audience and want a real sound of a complete band in a keyboard instrument. Perhaps they are few, but they still exist.
About audio styles flexibility (again, only my opinion)... For musician they're flexible enough to use (at least on Ketron), however they're very difficult to create from scratch (compared to normal midi styles). We need to keep in mind that music differs extremely around a globe... where can I find audio styles for music that's popular in my country?
Well, creating complex voices on a synthesizer is not so easy and quite laborious either. I don't have a true synthesizer at home to speak about it, but I see that the vast majority offer much more resources and creative possibilities for the user than arrangers.
If you can't find audio styles for a particular musical genre, you can create your own from scratch. There's no shortage of loop libraries nowadays, with various types of instruments and grooves. And you can even record your own if you play a different instrument. In the end, it's the result that matters most and will certainly yield many fruits. But the reality today is that musicians want to do more with less.
I guess Yamaha quickly realized that it can't (or don't want to) compete with audio styles.. because Yamaha wish to have uniform development process for all arrangers they make (from 600-5000€).
As I said, it shouldn't have even started. They introduced the feature in several of their keyboards only to abandon it later. If they did it, it's because they saw something promising in it.
Yamaha will continue to sell keyboards to consumers who buy them to play at home and simply relax, or in bars/restaurants, as is common in Brazil. However, on the other hand, they will lose ground in the market to musicians who truly seek the best sound that an instrument can offer. And then it will always be small in comparison to others. I don't want to offend more passionate users in any way. As I've said in other topics, I'm a big fan of this brand, owner of two good keyboards, but that doesn't take away my right to express my opinion, and this forum is here for that.
Best regards,
Gabriel