Some great ideas there jonasan.
The concept of a character having proficiencies and deficiencies in certain elements sounds great. Just remember that characters can be very short lived, in which case you'd modify your spell selection for a character that dies right away. So perhaps it makes more sense to have all characters from a certain time period have certain proficiencies and deficiencies.
I also thought of the idea of having shields (magical or tech) that you can only get past within a certain range. You could also have invisible monsters that only appear within a certain range, or really tough monsters whose innards can be hit from close range but who 'pull their innards back inside' if you hit them from afar. I think these enemy types are a must if we're going to balance the utility of long range spells with other spells. Also, some enemies that can only hurt you if you're far away from them would be helpful (like having missiles that can't lock on you if you're close).
From the ongoing discussion, it seems to me like these should to be the requirements for the spell system:
1. Every player should be able to choose their own different selection of spells.
2. There should be a reason to at least try different spells, if not in one continent then over time.
3. Being forced to randomly use spells you're not used to once in a while makes for interesting gameplay.
Rule 4 is implicit, in that the utility of spells should be more or less balanced. Currently long-range spells dominate, but I think that can be dealt with using enemy types as stated above.
So far, the possible ways to mix up spells that have been suggested include having the spells themselves be shuffled between tiers, having characters produce preferences for different spells, having the monsters serve as challenges that drive different spell use, and having access to tiles drive different spell usage.
While I'm fairly partial to the idea that spells could be shuffled between tiers, there is a downside to that, and that is that it doesn't meet requirement 1 very well -- if certain spells are locked out per tier, it makes it hard for players to choose their own palette of spells unless there are MANY spells in the game, in which case locking out some doesn't make a huge difference. Also, there are already more organic ways of randomization in the game (namely the tiles) and this scheme doesn't work into that.
The character and monster options don't seem to require much specialization or changing one's selection per continent. Both options seem to leave the spell selection process mostly as it is, but perhaps someone else could expand on how they relate to the requirements I stated above.
To me, the most potential seems to lie in the tile-based option -- this is a source of randomization per continent that I feel should be exploited, and currently it isn't really. It doesn't matter which tile is next to which other tile -- you can easily access them all. I love the idea of certain tiles being inaccessible (or difficult to access), but that eliminates the 1st requirement -- those spells are cut off for everyone on that first continent. While I think this is also good to have, I'd like to suggest another take on this idea.
I think it makes sense to suggest that the settlement is completely surrounded by storm initially. It's the only place that the wind has been driven away. Each glyphbearer then gets a small way to drive the wind out of one or two tiles initially in the general vicinity of the settlement. This is like placing your first settlements in Settlers of Catan, and I'm sure it's analogous to something in AI War too
You're essentially declaring which region types you'll start exploring, and which ones will provide you with resources. Perhaps this way of driving back the storm is temporary. As additional bonuses, the feeling of oppressive storm is even greater. Also, this makes every resource you uncover (gem vein, stash) critical, because you don't initially have easy access to many tiles. This will really contribute to the urgency of the game. As you expand your sphere of influence, you'll have to choose which direction to move in to push back the storm, and it'll only be a few tiles at a time until you build a wind shelter. These selections will determine your spell types. Each glyphbearer in a multiplayer game could start in a different area and therefore have different spells, and the spells would be a mix of what's available and what's determined randomly.
As a variation on this idea, each glyphbearer needs a resource harvester of some sort to be placed in the tile they want to start collecting gems in. Glyphbearers could cooperate and place their harvesters in the same tile, or they could place them in different tiles. The harvester can only move slowly between tiles, meaning that the player relies mostly on gems in a certain area to supply his spells. Each player chooses a different starting point though, and therefore each player can have a customized selection of spells (based on a combination of preferences and the randomization of the continent).
There's a lot that's vague in these ideas right now, but I think the upside is that they satisfy all 3 requirements.