This is overall much better with a G.axe for high TP return than dual wielding axes as the ability will only guarantee the next attack from the mainhand a second swing.
G.axe-
For me, I'd rather not use this ability on WS, but instead use it to build TP. The damage input to the WS with this ability is about as much as a regular attack, so unless you're gonna SaTa+WS onto a tank to open light, you should might as well use it as a TP builder.