dgx 305 keys and action and atleast 1 GOOD ac piano sound (without aftertouch if they can't ),(min 20-22 watts like pa80) speakers,psr 3000 board,1 more input for instrument,weight under 12kg and they will sell like pound cakes.

cause the only reason that 305 is not outsolding say 1500,3000 is lack of 4 variation ,style creation and pads.people care less about 6 trk seq when the have a good looking(non cheapo look and feel-except for the buttons)SM equipped machine with plays mid file/styles with no loading.

it also look like a good investement(looks good in living room) and the look doent age as fast as 2k,21k,3k stuff-the rear has only YAMAHA logo with decent and expensive look without the model number (like expensive EPs) ,good piano box keys mean it can make/inspire you to learn and play unlike thin short keys.

so 3k board,above features sell under 1500 or 1700$(no need for 88 key model) they will outsold roland and korg cause yammy' only major problem now is the keys and built quality these days since competitions are still 2 times more expensive9WAY OVERPRICED)- and lack of vital realtime features.YAMMY can sell tens of thousands.