I feel that nowadays, pretty much everything that is sample based, whether it's arranger OR workstations, if you didn't like the SOUND of the previous incarnation of whatever you are looking at, you aren't going to like whatever is new. Probably at MOST, any new keyboard only has about 10-20% new samples, the rest is just rolled over from the previous model.

Synths are a somewhat different kettle of fish, as the voice architecture is what determines the overall sound, but once it is samples, especially of acoustic instruments, there's not a lot you can do to radically change them into something noticeably different AND better...

So if you disliked the previous Korg, Yamaha, Ketron, Roland, whatever, it is pretty much a given that you are going to feel probably the same about any new model. Maybe over a period of 10-15 years, you might see enough of a difference to change your mind about them, but from one model to the next?

Not going to happen, IMO...