I can't overstate how important it is to me and my playgroup that all expansions include 4 of each card.  This is so important to most gamers that fantasy flight actually went back and re-released most of their older "a game of thrones" boosters in a 3x format.  Please, please don't put us in the position of having to buy multiples of the same product to play the deck we want.  The fact is most players simply won't.  They'll either play a different game or just make proxies of the missing cards.  The only players who will buy multiples are those few who plan on playing in "official tournaments" if and when those come into being.  

I understand why the core set was released the way it was.  I'm really hoping that between the core, first, and  second core spell tomes we will have 4 copies of each core spell.  

Regarding how expansions are packaged thematically:  this is so much less important than card distribution that I almost don't want to comment on it.  Almost  I'd suggest thematic expansions that provide a balanced selection of cards for all schools of magic.  This will help prevent various mages from dominating simply b/c they have more spells available - as would be the case for individual mage or school of magic expansions.  Also, it will help you business model as it will encourage players to buy each product.  The end result is selling more (good for you!) and players being happy that they don't have to buy multiples of the same product (b/c they will be released in 4x distribution, right?)

(one other option would be to do a fixed 2x distribution.  This might be a valid compromise that would still allow players to easily have a complete set of spells)

I'm nearby in Davis.  I know Mage's Realm in Sacramento is a great place to play - super friendly and lots of room.  They've been really supportive of getting other game nights (i.e. Serpent's Tongue playtest) going as well.  I'd definitely be down for meeting there once the game is released.