I'm not a big fan of having to go through iTunes for certain things either. And a USB port would be nice. I don't think those criticisms are invalid.
I really don't like iTunes, it used to run incredibly slow on my old computer and I know part of it was older hardware but it still should not have essentially locked down my computer just to sync my iPhone. iTunes runs much faster on my new computer with an i5 processor and 8GB of RAM but I still don't care for it much.
I really wish you could setup and update the iPad without having to go through iTunes. I'd like to get my 76 year old grandmother one so she can video chat with her great-grandchildren. She's never used a computer in her life but I know she's willing to learn and the iPad seems like an ideal way to do that given that it's easy to learn and hard to mess it up (compared to windows for example where you can get into the system files and screw them up by accident if you don't know what you're doing). I wouldn't mind setting the iPad up for her and syncing it for updates periodically but seeing as how I live in the US and she lives in Belgium that's not really an option.
I would also really love a USB port and expandable storage with micro SD cards (but yes I realize Apple would lose a lot of money but it annoys me because I feel ripped off to pay $100 more for my 32GB when I know a 16GB micro SD is much much cheaper). As an amateur photographer, I do love the camera connection kit.
All in all though, I knew about all these limitations when I bought the iPad and I still love it. I do believe it's the best tablet out there hands down. My brother wants a Xoom and I just laughed at him and said go for it, I'm sticking to my iPad (which my mother played with once and now she's calling stores trying to find one in stock!).