I'm posting this as a separate answer because it is pure opinion.
Performing input & output (particularly input) is a very, very hard problem, so not surprisingly the iostreams library is full of bodges and things that with perfect hindsight could have been done better. But it seems to me that all I/O libraries, in whatever language are like this. I've never used a programming language where the I/O system was a thing of beauty that made me stand in awe of its designer. The iostreams library does have advantages, particularly over the C I/O library (extensibility, type-safety etc.), but I don't think anyone is holding it up as an example of great OO or generic design.
