Well, obviously at the moment Roland (and most of the majors) are developing styles for their existing customers. It's easy to see a bias towards, firstly, 'older' styles mostly usable by senior citizens, or players playing FOR senior citizens, and secondly, styles aimed squarely at European players, beer-hall and schlager, and european flavored 'pop' styles.
If arranger manufacturers want to get serious about the US market, they are going to have to make the styles FIRST, and then the sales will come. It's not going to happen the other way around, for sure....
As I've said many times, if arrangers (in the US, at least) had styles developed by the same teams that voice the arp patterns for workstations, you wouldn't be able to keep them in stock! Manipulating a style is FAR easier than trying to string a bunch of patterns together on the fly.
I tried a MotifXS recently, and while the patterns were to die for, hip, contemporary, VERY 'USA", it was a nightmare to try and trigger the patterns and fill patterns while I was still playing other parts...! An arranger is a FAR better tool for manipulating patterns, but until the majors stop giving ALL the good, contemporary patterns to the workstation line, and stop leaving the arrangers with mostly schlock and old folks home styles, this type of keyboard will never increase it's market (and slowly die out due to attrition!).
It isn't all about the $$$.... Sometimes you have to INVEST to get $$$$ in the future....
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An arranger is just a tool. What matters is what you build with it..!