The problem with tablets is they're incredibly limited. The hardware seems to improve with every generation, but specifically in the instance of iOS: the software seems to be stagnate. What's the point in having super fast storage, quad core processors and fast memory if the software is so limiting and horrible it doesn't let you take advantage of it? As a developer, I find iOS to be a horrible operating system and v…
I don't even think they're particularly good at surfing the web. The interface on the iPad (and perhaps tablets in general) is simply too limited to be useful for much other than basic surfing. It's annoying really, because many sites try to be tablet friendly and ruin their desktop experience to fit the tablet needs, but the tablet still isn't really as good as the desktop ever was.
You may be correct in that it's the software, personally I think it's the touch screen that's the limiting factor.