Knights indeed can block :)

[Ulti19]

With auras it will be a nice spell but I notice that it has another awesome use. At Herb when I stood in front of team elves were unloading on me, despite the fact i'm a knight, and tons of mana is lost on their part because everything is blocked and after 30 shots I get one heal and am back to full power lol. This move has hidden potential even in current state, especially lv 5^^
On another note, I doubt it will get nerfed because you really cannot do anything when you are in this mode. It's up to the enemy whether or not you get hit and waste shots on.