Also similar variations have been discussed throughout forums.
6-dicing spells of ultimate destruction sequentially and/or on first turn, to ensure they go off reliably, can precipitate a lot of frustration from opponents. The threat of miscast exists, but the amount of dice committed is irrelevant for the severity of the miscast (and thus not a deterrent). On the other hand, a unlucky miscast on few dice can be horribly crippling, and kill an entire game due to bad luck.
PROBLEM: The severity of a miscast is completely unconnected from the amount of dice committed, leading it to be little of a deterrent when considering 6-dicing spells.
SOLUTION: When a Wizard miscasts, roll D6+(number of power dice used). Refer to the following table to see what happens:
D6+power dice Effect
3-4 Magical Feedback (allied wizards take S6 hit, lose power dice)
5-6 Detonation (S10 hit to all in base contact, lose power dice)
7-8 Calamitous Detonation (S10 under small template, lose power dice)
9-10 Power Drain (-D3 wizard level, cannot cast spells that phase)
11-12 Dimensional Cascade (S10 hit under large template, wizard or power dice lost)
The details of each result above are as described in page 34. of the Warhammer Rulebook 8th ed.
Note: if a miscast is triggered by an effect that did not involve spellcasting or use of power dice (such as the Hellheart), assume that 2 power dice were used for the purposes of the roll.
Note: if a miscast is triggered by an effect that did not involve spellcasting or use of power dice (such as the Hellheart), assume that 2 power dice were used for the purposes of the roll.
This change simply reorders the miscast table, and makes it progressively worse depending on the base number of dice used. This causes that triggering a miscast on a high number of dice is an extremely risky proposition, either risking losing Wizard levels or a Dimensional cascade. Throwing more dice at a spell is literally playing with fire now. On the other hand, unlucky miscasts on a few power dice are no longer crippling.