Fair enough BN, I guess I'd also subscribe to a keyboard with sampling "reading" capabilities.
The only thing is that I don't think that Yamaha designed the Tyros to be a professional workstation (even though they use that name). That's what the Motif is for. If they would turn the Ty into a real workstation, it would completely destroy sales of the Motif. Their other choice would be to design a Motif-Tyros keyboard at the price of both put together $5000.
Considering that it is not the intention of Yamaha that the Tyros be a workstation (whatever they choose to CALL it does not really matter) - I think it would still be a preferable option to have the ability to insert plug-in boards over sampling. I guess its the quality vs quantity debate.
IMHO, arrangers are "Quantity" - many and all options in a single unit;
and workstations are "Quality" - great and the best at what they are designed for.
Once again, my 3c,
Chony