So are Talismongering and spell design to be replaced by "Arcana?"

Ah, yes. That pesky active skill listed right below Arcana.

I am kinda curious as to what Arcana will actually cover.

My first guess would be that it replaces Magical Theory, but Magic Theory seems like it is more a Knowledge skill than an Active one.

Maybe teaching spells to other mages?

<shrug>

You don't think it replaces Talismongering?

Arcana might be for something like acting on magical theory. Like Spell design, or maybe even dealing with magic effects. Like aligning, cleansing, or handling wards or circles or something.

I'm just saying that because it is suppose to be active, and it is Logic based. So that springs to my my the hermitic symbology stuff.

Arcana is indeed an active skill and it represents the physical and ritualistic translation of magical formula (all types of formulas) - to find out exactly what it does you'll need the book but you're on the right track. Perhaps the best parallel I can make is that it relates to Magical Theory Knowledge skill in the same way as (vehicle type) Mechanic skills relate to the Engineering Knowledge skill.