I just got my first iPad around a week ago and really have been enjoying it. That being said there are a few things missing ( in iOS) that have become even more annoying since I have added my iPad to the mix.
Me and my girlfriend both use iPhones and now with an iPad around as well it is impossible to tell which device has received an email when it dings. This is such a huge oversight on Apple's part. My Blackberry, W7 phone, Android devices all have this feature, seems like someone at Apple forgot and they just never got around to adding it.
Flash. I know I am beating a dead horse but since I purchased an Android phone for my work phone I find myself using that for browsing over my iPhone. Why? Because if I am browsing and I end up on a page that has a flash video on it my iPhone won't run it. The same thing can be said for the iPad. People say that flash is dead and HTML 5 is the future. May be true but it doesn't mean that the ability for a device to run flash is pointless. If this were the case every OS Apple releases from here on out should have no flash support, see how that goes over. The device can run flash, get over the little tiff with adobe and get it in iOS5.
The overall look of iOS on an iPad comes off as weird. I don't think it looks bad, but it does appear that 90% of the screen is not being used. The dock can do 6 across, why can't the rest of the screen. I feel that with all of this screen space Apple could do a better job using it. Since iOS was originally designed to run on the 2g iPhone and has not seen any major visual changes ever, it just looks plain. It WORKS fine, but doesn't look any different from my 2G iPhone really.
Not trying to bash Apple or the iPad, heck I got one, but some of these small details could make a really good product into a killer one. If this played flash, and was bit more customizable, this would be a product that was a generation or two ahead of anything and everything else out there.