I would question a buckler's efficiency when strapped to an arm - at that point you may as well just wear a gauntlet or an armored bracer and Wonder Woman stuff.  I mean yeah, it can be done, and we all know that inhumanly perfect timing/precision of action is the [i]true[/i] universal RP superpower, so you could make it work...but I feel like having the shield immovably strapped in place would strip off a lot of the normal utility of a buckler.