Increasing her movement speed is a huge nerf. She used to be good for killing even legendary heroe by hiding in the group. I can still win in arena with this tactics against all legendary heroes players of similar level. Now, she is always in front of her group and get destroy easily by any legendary heroes she encounter. There should still be opportunity for players without all legendary to win in arena with some smart tactics and good heroes composition, rather then auto win with all legendary. I have been monitoring this change and my rank have been push down significantly eversince the changed was made. Can't really competit anymore.
For attacking, you place it solo and hope it is solo and you'll usually win.
For defending, ninja and assassin are the only "real" defense. Placing them in a solo lane and hoping your opponent chooses other lanes is about the only way to defend. The attacking team generally has a big advantage, otherwise.
Idk how she is intended but...
I am better off not using her at all than using her in the same lane as my other heroes. She just gives the enemy heroes energy, while mine stay flat. They proc first. I die.