I wouldn't go as far as to call the NP30's action 'graded' anything. It's basically a no-weight action little (if any) better than the S900 (which is why I feel it would be a success and appropriate quality level for what Yamaha thinks PSR owners deserve for the money ). Other than stretching the case, I see no need to do anything different to the arranger. Why split and complicate the issue if a simple addition to the line would accomplish more than some bastard DGX (which you KNOW Yamaha will dumb down) version of the S900?

Sure, I'd LOVE to see an FSR keyboard added, but it's just not going to happen unless to the T3 line... To be honest, I don't think the NP30's keyboard would slow ANYONE down, even those used to the S900's...
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An arranger is just a tool. What matters is what you build with it..!