Yay for a little bit of thread necromancy. It's just that it occurs to me that, overall, if one wishes to run a game set in the Wheel of Time universe, it's incredibly important to know what exactly you want your game to be about. This is going to affect many things about the game, after all.
Say, for example, you want the game to be about four callow youths and their adventures as they leave their little village in the arse end of nowhere to do great things. At this point, they're probably not going to have many weapon proficiencies, they won't be trained in the use of the setting's magic and any encounters they have with those who are will probably be short and mostly social in nature (either that or sticking a bit of sharp metal in their back while they're not expecting it), with open combat being borderline suicidal against men, or simply embarrassing against Aes Sedai.
Alternatively, the game could be primarily about military campaigns - at which point one would have to leave speculation until we know how mass combat is handled (topic for another teaser, perhaps?
). There are many wars in the setting's history, and there's always the potential for more in its future. Playable channellers could show up here, either because the army is made up predominantly of such or because the army has a unit of channellers - the head of that unit would probably be one of the general's lieutenants.
Also, there are more political games. Channellers could show up here as well, though their channelling would likely be mostly limited to such simple tasks as warding against eavesdropping or occasional self defence against assassination attempts (or, in the case of the Black Ajah, making the attempt). Campaigns revolving around an investigation could probably work in much the same way - digging up evidence isn't all that different from digging up dirt, and the two could potentially cross over from time to time.
Finally, we have the Band of Bastards game - a collection of thieves in a big city would probably not have access to a trained channeller - though an untrained one might show up, causing problems all of their own (especially if male).
At this point, we need to decide just how channelling would affect any given story. For the Callow Youths, any amount of channelling is likely to be done by an NPC - either in the form of story based mechanics (Aes Sedai rarely do favours they don't expect to be repaid), creating a weapon using the Power with which to attack in melee or ranged attacks the player characters can potentially dodge. This also goes for the Band of Bastards.
In a military style game, channellers are basically going to be a combination of archers and walking artillery pieces - either killing enemies one by one or tearing the battlefield asunder with powerful explosions.
In a political or investigation style game, channellers may possibly come into conflict with each other, so here is where it's most important to be able to capture that.
Firstly, overall strength in the Power is measured by a separate Attribute, to be assigned points from the Attributes priority (assuming that priority pick is still a thing), while the ability to channel in the first place would be covered by an Edge. Assuming a scale of 0-5, a 0 would indicate functional inability to channel (either through lack of training or lack of natural talent), a 1 would allow for basic effects (think Prestidigitation in D&D), but no real attacks. A 2 would be the minimum with which you could actually attack (and would be the minimum for a fully trained channeller, as anyone less strong would be kicked out), while a 4 would be the minimum for a travelling gateway that a human could walk through.
The different elements would probably be handled as Proficiencies (with points taken from that pool in character generation), with specific talents given as Edges which allow Power to be considered higher for the purposes of being able to use specific weaves (such as healing, travelling or cutting someone off from the Power).
Using the Power in combat would likely have a subsystem similar to that of melee - direct attacks with an element which work like thrown attacks, non-damaging effects which affect an opponent's ability to fight properly and so on being the offensive weaves, with attempts to dodge or to slice a weave and prevent it from working being the defensive weaves. Some, like shielding someone from the source, could be used both in defence and offence. This would probably be largely modelled on the magical duel system from Blades of the Iron Throne, since that's where I got the idea from.
These are just a few thoughts that came to mind as I eagerly await the beta.