The Arcane Destruction on the Archon skill causes an explosion when you transform to the Archon form, causing 450% weapon damage as Arcane to all enemies within 15 yards. Will the enemies killed by the explosion will count as enemies killed by the Archon form and increase the time of the form?
No, Arcane Destruction kills do not count towards increasing the time spent in Archon form. I tested by taking my wizard to Iskatu's fight in Normal, building up a lot of shadows and then blasting them by activating Archon form. The resulting timer was still 15 seconds :(.
I actually expected the opposite, but it seems that Arcane Destruction isn't counted among the archon kills for increasing the timer.