I do believe we are assuming too much about Honorblades, it can´t be that they only give you the equivalent (if more consuming) power of a KR, granted, that would be an incredible power. BUT! i really don´t think that a Honorblade has only THAT ability.
Having that in mind i believe that Taln´s blade or any Honorblade can actually be picked up by anyone and get the ability of a KR BUT! as it is not unbound as the other Honorblades Taln could summon it at will and make full use of it if he chose to, but ofcourse he cant because well...torture HEEELLOOO! xD well that´s what i believe.