Yeah, looking back at all 3 miscast tables... the only things that cannot be tanked or ignored are mental block (very short duration reduction of Magic, not that bad but could still be a nuisance) Silenced (dependin on the situation we may need our voice, but its still a one day nuisance otherwise) Overload (1 turn stuns can be the difference between life and death in a fight... although if we can tank the opponent its moot) Chaos foreseen (which we can tank mentally, considering we are much stronger mentally than the average warhammer human thanks to our learning and magic stat) Mindnumb (same as mental block, butfor 1 day, making it more troublesome but ultimately not very harmful if you have high magic) Daemonic possesion (ooooooooof ... that is the first one that is REALLY not worth the risk, even if its just for 1 minute) Wild Magic (it hurts our friends) Tzeench's Lash (one should be able to tank that going by logic, but by the rules as written, you get knocked out for quite a while, which will be lethal in battle against peer opponents) Heretical Vision (same as chaos foreseen but worse) Moindeaten (magic burnout that returns gradually? big oof) Daemonic contract (if we even hit 13 of those, which is unlikely unless we make a habit of miscasting) Called to the void (the aforementioned sucked into chaos one) and any of the "QM decides" ones, which prolly have a much higher probability here because Yrs wouldn't want us to ignore miscasts even we find a way to tank every single effect unless said way is divine ascension.
On second thought... I was wrong. Miscasting is still ultra bad even when it is less so. Welp.
