People want a totally different variation everytime. Same with the iPhone.
There's only so much you can change. And the new iPad has changed all the important parts.
Apple aren't bothered about getting people to upgrade, as nice as it is for them, they know that people who spent £400+ a year ago aren't likely to want to spend more money on the new one.
But there is still millions of people, like Nero, that haven't got any form of iPad. They see the new screen and decide now is the time to buy one.
No matter what had changed, some people wouldn't want to upgrade. The iPad2 is still the second best tablet available. By a long long way. It's not suddenly awful because there's a new model and for millions of people it will be fine maybe until next year, or the year after, or the year after.
Some people like to buy s**t with plugs. Some people like to buy watered down beer and be sick all Sunday. People are different. The latter seems to be accepted. The former makes you a fanboy.
If you want to upgrade or buy it. Then do so. If you have an iPad2 and don't think it's worth spending the extra, then don't. Nobody is forcing you. But it IS better. In all areas. But that doesn't make the iPad2 a bad tablet.