If you are expecting Yamaha to offer anything cutting edge you will be waiting a long, long, long time. Large manufacturers such as Yamaha, Roland, and Korg would never offer a keyboard with all the features that you want or expect because that would be very bad for their business. If they did do that then you'd buy their new keyboard and it would take another 5 years or so before technology would advance far enough for you to ever consider buying a different instrument. This means you'd no longer be in the market for a new instrument which equals less revenue to the manufacturer and that simply isn't going to happen.
I see many people post on the BBS that if manufacturer "Y", "K", "R", or "Z" offered an arranger that had 76 keys, Gigabytes of RAM, lots of sounds, real time editing features and controls, tons of outputs, and future expandability they'd definitely pay more and buy it but that isn't true. People want the world but most often they want it at a bottom line price and technology that is at the forefront is never cheap. Perhaps if the keyboard costs an additional $200.00 or $400.00 maybe then you'd buy it, but if it were an additional $2,000.00 or $4,000.00 would you buy it? ... Probably not. If this were true then you'd see more manufacturers marketing ultra high end instruments because the customers would be there to buy them. Business is business and if a large enough market existed for these types of products, companies like Yamaha and Roland would make them.
The fact is there are keyboards available today such as the Wersi Abacus, Wersi Ikarus, and the Lionstracs Mediastation X-76 that have Open Architecture systems that will do most anything users want of them. These keyboards offer huge amounts of RAM for sounds and styles with nearly unlimited upgrade possibilities, large color TFT screens, more outputs and real time features than any current arranger, and yet few people own them. Is this because of bad marketing and limited distribution? Not really. Its because there aren't many buyers who would spend $4,000, $6,000, or $10,000+ or more on a musical instrument. Sure you say that you would but ask yourself ... when's the last time you paid over $6,000 for a musical instrument let alone $10,000? I'd guess fewer than a handful or so of Synthzone members could answer yes to this question.
Until the time comes when we are willing to put our money where our mouth is, manufacturers will continue to offer low to mid priced, rehashed, reworked instruments that use outdated technology put inside a fancy new box that offers relatively nothing new. Until then only a few small manufacturers such as Wersi and Lionstracs will tow the line hoping to sell enough of their cutting edge instruments so that they can continue to offer what is at the forefront of technology.