Very thoughtful article vitalog2010. I like that you also mentioned things, that might not be that important for your needs, however they are important in general. I think, most (if not all) of things you mentioned, also apply to PSR-SX series, which Yamaha promotes as "semi-pro" (and prices confirm that).
For me, it's not about Korg vs Yamaha. As Yamaha owner, I don't care what Korg has.. I only care about things that my Yamaha is simply missing (or is poorly implemented). On the other hand, one just can't not to see the facts... here in Europe, five years old Genos is about 5800€ and just released Pa5X is 5000€ (4300€ for 61 key version)...
You mentioned balanced audio connections, which is a perfect example. Calling some music instrument (semi)pro, without having balanced outputs, is a plain joke. I mean, every musical amplifier (or active speaker) above $100 has balanced inputs! -there is a reason why balanced connection was invented for live music performing (very long time ago). And then skimping on onboard user memory.. nowadays? No wi-fi/bluetooth built in.. nowadays? And the list goes on.. things you mentioned in your article.
Don't get me wrong: I'm happy with my SX700 and I don't regret buying it. But I don't pretend to think I have some "semi-pro" instrument -it's just an well featured home arranger keyboard. What would Yamaha need to do, to convince me to buy newer PSR-SX? Besides some of the things vitalog2010 mentioned, it has to have keybed of better quality -these clunky keys in current SX-es are embarrassing.
I'm aware this is a Genos forum section, so I apologize if my post doesn't fit here.
Thanks for reading,
Bogdan