Its not a retcon because they never said that mysticism didn't exist, simply that it does not exist in the present, which is perfectly acceptable and not a retcon in the least. You need to check your definition of a retcon.
There's more than one definition to retconning. Retconning can mean to add info explain a mechanical choice. Look it up.
Plus its more than just "some names a mage gave it", Again, know the lore/canon.
It's still the old way, Mysticism still exist, but not by the mage's guild standpoint, or whatever reason mysticism isn't there.
If you still don't believe it, then where's Thaumaturgy, and Necromancy?
If you still don't believe it, then where's Thaumaturgy, and Necromancy?
Necromancy has never been a PC skill. Thaumaturgy has no lore and means miracle working.
I also find it funny that nobody read the book I linked and would rather just continue arguing about somthing they apparently know nothing about. Mysticism is the oldest school of magic.