I beg to differ and even add an: On the contrary!
Adolin stems from a culture, where shardblades are coveted and venerated objects. Up to a very short time in the past they where mysterious, too. People only knew that they where immensely powerful. Quite some of them where named by their owners.
My point is: an Alethi like Adolin, educated for warfare, had of course a very personal relationship to his shardblade, even before he learned (less than two years earlier!!!) that they originally had been spren. Hardheaded as he is, he just refuses to change his ways of handling his sword of caring for it, just because, you know, Modern Times.
It might well be, that this is the core reason, that radiancy for him is further away than for many others.