Well Guys, the fact is, the key of the success of iPad was that apple finally being the first who had understand what's the necessity of being a portable computing device.
Which is being "portable","easy to use" and "a kick-ass battery life"(Despite it's actually pretty fast and smooth, right?).
I think I don't have to remind people that Apple is not the first one who make portable computers, but why it could be the only company that survived in the market? Well, we all see how successful it is. And why? You think it's simply because there's no competitors? But the truth is that the competitors have been there for years, just no one cares.
Yes, an iPad doesn't have the jumbo features like HDMI ports, USB ports, Firewire, or SD Slots so far, but there are a lot of other better choices than a portable device for you to get a better experience with all these jumbo juicy snacks, but they are just not portable, or not fast, with extremely short battery life, which basically lack of everything of being a kick-ass portable device.
Also, I found some people here are quite amusing as requesting for a higher resolution to support the HD movies, not that higher resolution is bad, but what are you guys expecting from a 9.7 inch "large" screen? Don't you think that those big-ass flat TV screens are more capable of giving you a true HD experience? And 16:9 ratio screen? Hell no, please, how would I read my ebooks in such a narrow width as portrait mode? Isn't it too much like reading a flyer? And what about displaying pictures? Surfing web?
No... for next generation of iPad? I wish it could be faster, more stable, higher resolution is ok, maybe an isight, that's all. I have many computers, I don't need an iPad doing too much, better user experience of doing specific things is more important to me.