I think that std::vector of wrapper class such as the below (std::vector<atomicwrapper<int> >) is safely used when JUST ELEMENT ACCESS is used. (elements are constructed in the previous )
each element is accessed by get() function as reference.
Is your question whether a vector of atomicwrappers would be thread-safe to, for example, resize in one thread and access in another? If so, the answer is obviously that it wouldn't be.
As you said, STL container operation such as resize is oobviously non thread safe.
Limitted to element access, is it thread safe? For example, get function of the above example. This just entails reference access before atomic operation.