Should Deathbringer Spells Cost HP? (Patreon)

In the new version of Deathbringer, spells require HP to cast. One of my patrons, Jay, pointed out that I already require rolling to cast, "1s" result in critical spell failure, and you can only get spells if you find them or another wizard gives them to you--so loss of HP feels like unnecessary nerfing. Also, in my magic video I said, "If a fighter can swing a sword every round, why can't a wizard cast magic missile every round." (Hoisted with my own petard!) Do you agree? 

I'm especially eager to hear if you've used these rules. As always, I reserve the right to dispute the winning side, but I am every interested in feedback.