Your spell's target is sometimes cast at self or random target instead of the intended target.

Rare if the % penalty for casting offensive spells remains in place.

Not-so-rare if the % penalty for casting offensive spells (because of miscast magic only) is removed.

I don't think it's very often that people take the flaws that exist right now. Adding more just doesn't seem worth it unless it's something with a lot of flavor (something highly visible to others).

I'd like to see them. I run into people with flaws all the time at the low levels. Not very many at hero though. Besides, an idea is just an idea, whether it gets implemented now, 2 years from now, or never.

I don't have any stats but as a random example I took myopic yesterday and tried to find any heroes with it and no one showed up at all in the PBFs. I assume they all petered out before that point. Thats kinda why I don't know that it's worth it, people like the idea but they don't want to actually put up with the flaws.