https://www.youtube.com/watch?v=L7xktwZNL9E
The above video is from the vanilla client showing a mage wearing what seems to be ~250 frost resist, evident by the lack of glacial shoulders & no use of a frost resist juju. By watching the combat log you routinely see +259 mana returns. This is due to the Magic Absorption talent which returns 5% of your maximum mana when fully resisting a spell. With Frost Aura ticking and being applied so frequently, this was one of the only PvE raid encounters which made this talent valuable to mages. Throughout the encounter in the above video you can see the effect proc a total of 14 times for a return of 3626 mana.
Knowing this ahead of time I build myself a complete frost resist set with virtual maximum resistance (312 frost resist) expecting near the maximum resist rate since maximum resistance should yield ~25% full resists from spells by a lvl 63 enemy. This should have in turn provided a large return of mana. However, after the encounter I checked the logs to find this:
https://classic.warcraftlogs.com/reports/jhk1Q8wJxdTzZXM7#fight=30&type=damage-taken&source=58&pins=0%24Separate%24%23244F4B%24resources%240%2427006727.0.0.Mage%240.0.0.Any%24true%240.0.0.Any%24false%2429442%24100&ability=348191
and
https://classic.warcraftlogs.com/reports/jhk1Q8wJxdTzZXM7#fight=30&type=damage-taken&source=58&pins=0%24Separate%24%23244F4B%24resources%240%2427006727.0.0.Mage%240.0.0.Any%24true%240.0.0.Any%24false%2429442%24100&view=events&ability=348191
Despite a much higher near-max 312 frost resist… only a 1.6% resist rate was experienced, along with just 7 seemingly random magic absorption procs for a return of just 1,396 mana
There are 2 issues at hand:
-
The full resist rate is significantly lower than one would expect it to be, suggesting frost resist is not increasing full resist chance beyond the base 1%. This may have been intended, but the inability to resist the application of the debuff may not have been intended.
-
The procs of magic absorption seem to be completely random; sometimes between ticks, sometimes even on ticks when damage is taken, and sometimes oddly no proc at all when the damage is actually fully resisted (see: 3:27.005).
Conclusion: While i can only speculate, my belief is that the change to the Frost Aura mechanics removing the constant application of the debuff also removed the main source of full resists, breaking a unique mage strategy specific to this encounter of stacking frost resist as a means to increase mana returns from Magic Absorption.