To be honest, Flash RAM is a MUCH bigger thing than some make out (few have even commented). The ability to custom load the sampler with what you want without worrying about how long it takes to load (Yamaha arrangers have always been glacial loading samples), and then them being instantly available when you switch the thing on is HUGE.

Don't like Yamaha drums...? Well, there's the answer, plain and simple. Don't like the Yamaha piano? Load your own choice, have it all there instantly. This ability is worth more buzz than it's getting.

SA voices in styles? Yep, that's pretty huge too. And a significant increase in Mega Voices, too (hopefully, a lot more guitars).

One thing that intrigues me is this idea you'll be able to get a dumb lower keyboard, and have it integrate to make a 'home organ' type keyboard (or at least a two manual where you don't have to have them separated by a foot just to be able to see the lower keyboard's displays and controls). Now, this might not seem like a big deal, but it is likely that, in order to achieve it, Yamaha MIGHT have had to seriously beef up their MIDI implementation, which will help players that want a 76 or 88 wood integrate it into the Tyros's system.

All in all, if you see yourself wanting to use samples a lot, I can almost see a T3-T4 migration as almost worth it, and it's a definite step up from a T2 or T1. But outside that, it's still a tough call to justify a T3-T4 move.