A Primer on Damage Output for Magicians

[The Undying]

Depends on the Discipline. Elementalists for example are 100% Physical.

[Telarus]

The effect is (therefore physical armor applies), but you usually don't target Physical Defense with spellcasting (I could find a single one, but I may have missed it). Additional successes are based on Mystic Defense, which can be good or bad depending on what you are facing - but for the most part creatures have lower Mystic Defenses. The exceptions are mundane creatures who are very Perceptive compared to their size/agility (elephants), or highly magical creatures (most of these have very even defenses).

[The Undying]

Additional successes are based on Mystic Defense, which can be good or bad depending on what you are facing - but for the most part creatures have lower Mystic Defenses.

You are correct on this. However, we USUALLY aren't talking order of magnitude difference between the defenses - at extremes, maybe ~5. However, I make a point to note that "+2 Effect" on success is hard to come by for spells as it has been specifically designed out to make spells with this stand out.

This thread is also just about single hit damage, and I specifically avoid successes-based improvement. The more conditions that get pulled in, the harder it is to get your hands around the problem. Your point is valid, though, so IF the magician happens to be using a spell that increases damage based on successes (which, as I said, is going to be the exception versus the rule), then yes, there's a fair chance of an average extra +2 across the board.

[Dougansf]

Also, the rarity of Steel Thought compared to Avoid Blow is a (difficult to calculate) factor.