Concerns about having to meet multiple versions of Basel II across countries are certainly reasonable ones, and I take these concerns quite seriously. I believe Basel II implementation in the United States should proceed in a manner that enhances consistency with implementation in other countries; Basel II is intended, after all, to be an international framework for internationally active banks.
Moreover, although the QE tapering decision must have been made based upon a judgment of US economic recovery, some within academia still raise the possibility of secular stagnation.