Who here thinks they should have made "an object-oriented C" instead? I was under the impression that a big part of C's success (as a lingua france / lowest common denominator) is its minimalism. It forces only a few concepts on its users.
That's Objective-C in a nutshell. Or was, anyway. The most minimal way to have useful OO on C.
Of course, you could make it even simpler if you drop the "must be a superset of C"-requirement.
Objective-C is Smalltalk added to C. Objective-C without the C is Smalltalk. Which is, coincidentally, a very simple language.