Why the iPad was a disappointment

I was watching Steve Job's keynote for the iPad and it truly bridges the gap between iPhone and the Mac books.  But why didn't it wow everybody.  It did build up the hype similar to the iPhone, but it didn't create a WOW as much as the iPhone did.

It also is revolutionary device, taking the ebook reader technology to the next level with better color display, with a full (and even better) functionality of the iPod Touch.  But why do we hear numerous frustrations due to the iPad's lack of what their expectations held them to believe the iPad's supposed to deliver.

Now, consider this, what if the iPad came first before the iPod Touch or the iPhone?
Will the reaction to the  iPhone be the same as the iPad?