For the iPad to be successful, you'd have to butterfly a few things away IMO.
First, would be Steve Jobs's fight with Adobe Flash. IIRC, he thought that HTML5 would defeat Flash and predicted that within a year of iPad's launch (2010), it would the the new web standard. How wrong he was...what is it up to now? Last time I saw, Flash was being used by around 85% of the media sites? Big bomb there.
Second, you'd have to add a few more features to the device, since it was being marketed as a "post PC" product, such as:
- SD Card
- More memory
- Better GPU
- USB Port
I mean, come on, Samsung's Galaxy Tab has all that, and they're dominant in the tablet market now.
You'd also have to make sure Apple doesn't charge huge fees for the iPad. How could they think charging so much for what even a netbook could do, but cheaper, was a good idea?