If federal legislation requires reciprocity, the feds will be setting the standards. Currently Texas and several other states don't recognize Utah CHL's. The feds could force everyone to accept Utah's low standards, or they could enact such onerous requirements that would make it more difficult to carry across state lines.
Didn't happen with marriage or drivers licenses. This is not a fed ccw issue law.
Huh? Four states (AK, NH, WY, AZ) require NO permit for either open or concealed carry (though all will issue one for reciprocity purposes). From the anti-gun perspective, those would seem a "lower" standard than that of Utah. And one I would actually prefer.