In 2nd edition the danger of casting spells was tied with danger of insanity, and with dealing with chaotic forces.
In 3rd edition the main danger seems to come from stress/fatigue/wounds, and then to some degree insanity (from to much stress/fatigue). The miscast cards does not seem to contain much danger really (not compared to 2nd edition), I don't see any chaos manifistations anyway (do these cards come with WoM?).
If you chose to quickcast, you get around 3 challenge dice when casting most spells (1 for quickcast, 1 for the spell could be Flameblast, and finally 1 for the it being an easy challenge, or did I get this part wrong?). Not sure if I understand this correct, but you'd have to be insanely unlucky to score 3 Chaos Stars, and even 2 stars would mean Lord Misfortune hates you some. And then the results are meh... it's 1 fatigue/wound/stress here and there, but nothing "major" like minor mutations. Or is this considered major, simply due to casting often resulting in Miscast cards? Also in 2nd edition you could start on the minor table, and then with unlucky rolls end up rolling on the greater table, in 3rd edition and with the above example it's impossible to roll more than 3 stars.
I'm not complaining, just not sure if I understand the mechanics. I also know (and love) that you now use power to cast, so no more lightning bolt throwing every single turn.