I think that some of the dumbing down of chord type tracks and 3rd party tools for making styles has come as a result of the rampant piracy of 3rd party styles. I know I sound like a stuck record, but the explosion of 'sharing' everything you get on the internet has had some pretty serious consequences in so many areas.

There seems to be FAR fewer people making 3rd party styles nowadays, reducing the demand for advanced editing tools for arrangers. Plus, of course, there seems to be a real slowdown in innovation of the basic OS's, to add new chord types, and more natural voice leading between chords, etc..

Yamaha, Korg and Roland haven't added a new chord type in years. Usually, major, minor and 7th (and Korg add dim, I think). And the truth is, other than Korg, few of even the factory ROM styles, let alone 3rd party styles use these features extensively. You can, in theory, have a completely different accompaniment pattern for each of these chord types. Yet this is seldom used to alter anything but the basic chord tracks.

But you can also have a slightly different drum pattern (change some accents on ride or hi-hat, for example) and percussion track that changes depending on the chord. This would be an excellent way of getting rid of the mindless repetition that plagues auto accompaniment. But it is seldom used.