I wouldn't mind this idea at all, and I agree that without the quick dispatching capabilities of a sling the aggressive animals are a little more annoying.
I like the torch aspect too, but I don't think a little flame would be enough to scare off a bear of course

However to me this would just be an easily abusable mechanic, you agro a boar, deer, fox or something your self to kill it, and then could easily scare it off taking no damage and giving you plenty of time to hit it again.