Its simple, look at their hardware lineup and then this. If the rumour is true and this event is purely about this then :Why does it have to be amazing at launch? What a bizarre requirement. Why can't it be good to start and grow better with time?
Apple is the only company that if something isn't absolutely stellar right out of the gate they should close up shop and just give up... like every technology today that is seen as "best of breed" didn't grow into designation over time.
a) it has to be amazing if they give it all the spotlight (which I doubt and it will be as boring as the edu event last year)
b) there is something we don't know that will be amazing - again, really doubt that as recent years showed us that everything leaks and Apple "stopped" innovating.
So yeah, the reason why it can't be just good at start is because of all the other factors.
Regardless, my bet is on tapid stuff