I teach economics at a college and love my EE. I really don't know how I lived without it. To address your questions:
1) Android 2.2 will be an update at some point in the future.
2) There is no direct access to the Android Marketplace but there are lots of ways to get around that problem.
3) There is a slight lag in writing but if you write instinctively (without really looking at what you're writing) you won't notice it at all. If you tend to look at each pen stroke, you'll notice the lag but it's not significant.
4) No flash until the 2.x Android update
5) The camera is similar to the built-in camera on most laptops. It takes decent pictures up close. It can be a little pixelated and is bad in poor light. It works perfectly fine for Skype, quick pictures, and simple videos like student presentations.
6) The screen orientation is determined by a button, not gravity. This isn't necessarily a bad thing. I also have an iPad and it often changes orientation on me when I don't want it to change.