BBB and the original Weapon Rebalance Mod patch notes for Elven Axe / Kerillian 1h Axe:
As per those patch notes, it seems that the intended crit chance bonus for the push attack is 20%. However, in Patch 3.1, push attack was nerfed (perhaps mistakenly) to 10%. There is no mention of any nerfing to the Elven Axe in the BBB Patch Notes thread.
“The bonus crit was added to the push stab to make up for a lack of bonus crit on the other lights in comparison to 1h axe.” “Tying more power into pushattacks is a cool concept, especially when it comes to procing effects.” — With the nerf to 10%, Elven Axe is still underwhelming.