Suggested resolution [SUPERSEDED]:

Change in 12.3 [over.over] paragraph 5 as follows:

Any given function template specialization F1 is eliminated if the set contains a second function template specialization whose function template is more specialized better than the function template of F1. If there is no target, a function template is better than another if it is more constrained than the other; otherwise a function template is better than another if it is more specialized than the other according to the partial ordering rules of 13.7.7.3 [temp.func.order]. After such eliminations, if any, there shall remain exactly one selected function.