I don't think Apple needs to add USB, HDMI, SD Card slot, Cameras, Compact Flash Card slots. For me, this is a travelling entertainment device that I can do some light computing on. Unlike software, I can't just turn off stuff I don't use – I have to live with 5 ports junking up my sleek gadget, adding weight and taking up room, and just making it uglier. I'm going on a cruise later this year and I can't wait to take my iPad on board. SO much better than carrying a laptop around. I think the great mind hurdle for a lot of people is trying to define what a computer is.
It turns out that the iPad is a new sort of device. Just get it if you want it. If it doesn't do it for you, then get a netbook or something else. What Steve Jobs said is right... "netbooks AREN'T a new category between laptops and cell phones. They are just small laptops." That's no insult to netbooks, just that if you want a new product class it has to be different enough from the existing products. You might have to accept that this "other thing" doesn't do stuff your computer does, but it does do other stuff.
Where are all the people complaining that netbooks don't have accelerometers, touch screens, any applications actually made for them (you'll never find a new racing game that runs well on a netbook, because who is developing that?!), an app store with the simplest uninstalls, or that you can't read an e-newspaper on a netbook while standing up in the subway?
If you want a really good device, you have to decide what it is NOT. A fork doesn't become better if you tape a knife to it. Being true to what the device is and not trying to be for every geek actually makes it better for your intended customers.