As i see it the core language is not so much a problem, but the shitty standard libraries and most of all how shitty it encourages the use of hacks.
Considering the fact that it has very few extendable core principles and a mostly consistent syntax, i would consider it to be a well made language.
Most of the problems lie with the fact that it was designed as a lowlevel language before the 80s for harvard arch computers.
Becuase of that it lacks hashtables and friends, because of limited resources implemntations of such mostly had to be writen by hand to be usable.
To add further back in the days it must have took a while to compiler so i assume thats why the preprocessor is such shit.
Besides some syntactical troubles, that most languages have, the one thing that really disturbes me about C is that some operators are mapped to specific operations assuming they are basic while some stuff is not.
Example: + and * are usually cpu implemented operations, but there is no exponent operator, even if it were to exist as cpu opcode you would still have to use it and treat it as a function.
Perl 6 has this feature that operators are syntactic sugar for functions.
Not to mention the lack of builtin over/underflow protection, even possibilaty to check for without doing a needless arithmetic operation or using inline asm.
Even then you would still have to write a function for this sort of thing in most cases.
I dont wanna hang out the lisper, but anonymous functions are one of the best things ever and i dont really see why C doesnt support that sort of stuff, other than compatibility with harvard arch (im not sure if it can be worked around).
One thing for questionable for sure is why C doesnt support nested functions, i can do that with ease in asm.
However its utterly crappy libraries and lack of interactive features are inexcusable in 2012. They promote hackery and can make work such a pain in the ass sometimes.
I hate C now too, but you must give it credit for what it has got right and not judge it by its shitty users.
And the worst of all is not C in itself, but the brain rotting abomination called unix that it spawned.
Morons will do stupid stuff no matter what you give them.