They got move semantics, smart pointers, concurrency primitives, type deduction, etc. out the door first. While I agree that reflection is important, it's not as important as those. I don't see any problem with comittee's prioritization.
Smart Pointers: have to put explicit refcounting in the root "Object" class
Concurrency Primitives: dependency on the POSIX API and its various "ports."
Type deducion: a few extra keystrokes, a bit of extra ugliness.
Reflection: Duplicate all ivar definitions in several places (if you control all the code) / create a new C++ parser (!) in order to add the feature to the language (if you don't). Also, you have to learn a new MOS every time you work on a different application. Interfacing two MOSes is always a nightmare.