It's not a good set and this is why.

First, the damage you do is a formula that includes weapon (stam abilities) or spell damage (magic abilities). But the formula also heavily relies on the max amount of that resources. A character with 15k max magic, 1000 spell damage, 35k max stam and 3500 weapon damage will hit hard with a stamina ability (~10k damage) and PIDDLY with magic (~800 damage). Pelinals would bring this toon's spell damage up to 3500, but doesn't affect max magic. So now their stam abilities hit for 10k and their magic hits for 3k. As a result, the backup resource hits are mediocre.

Secondly, you've paid a hefty price for the mediocre magic hits. This toon could use Hundings Rage instead of pelinals and amp their weapon damage, to get ~12k stam attacks and 800 magic.

Third, using the alt resource for attacks is usually not attractive, even if you could bring the damage up to par with your primary resource. Stamina toons have plenty of choices for their magic to provide essential buffs, escapes, etc. Magic toons have fewer choices, but need stamina for dodge and block. There's usually not a compelling reason to tap into the alt resource for an attack. This is particularly true for your mag sorc friend...they want to tap into their stamina for exchange, providing health and magic in return, which is way more valuable than any stamina based attack.

For a mag sorc, almost any other magic craft set will outperform pelinals. Twice born is good, julianos is an all-around decent set, Magnus or seducer for resource management. Even shacklebreaker.