Not that I hold this up as the greatest method of determination ever, but the Wheel of Time Roleplaying Game book (it's official stuff, with a Foreword from Robert Jordan, who also later wrote an article for Dragon magazine providing more creatures for the setting) does give out attributes (and in fact entire stat blocks) for a number of important characters. A potentially important note before I share them here is that in the game system, channelling power is based somewhat off of the mental ability scores (Initiates, that is trained channelers, use INT and WIS; Wilders use WIS and CHA). Another note: it was published back in 2001 (working under 3.0 edition rules), meaning after Winter's Heart was published but before Crossroads of Twilight.
Rand: STR 13, DEX 15, CON 14, INT 16, WIS 19, CHA 22.
Mat: STR 13, DEX 20, CON 12, INT 14, WIS 10, CHA 16.
Perrin: STR 16, DEX 12, CON 18, INT 10, WIS 16, CHA 18.
Egwene: STR 8, DEX 13, CON 12, INT 17, WIS 20, CHA 18.
Nynaeve: STR 11, DEX 15, CON 13, INT 14, WIS 20, CHA 19.
Elayne: STR 8, DEX 13, CON 12, INT 20, WIS 18, CHA 18.
Aviendha: STR 12, DEX 16, CON 14, INT 14, WIS 15, CHA 16.
Moiraine: STR 9, DEX 15, CON 14, INT 20, WIS 16, CHA 17.
Min: STR 10, DEX 19, CON 11, INT 14, WIS 12, CHA 12.
Loial: STR 20, DEX 10, CON 16, INT 18, WIS 12, CHA 10.
Lan: STR 17, DEX 16, CON 15, INT 12, WIS 14, CHA 20.
Thom: STR 10, DEX 16, CON 8, INT 18, WIS 15, CHA 16.
Dain: STR 14, DEX 12, CON 13, INT 10, WIS 8, CHA 16.
Fain: STR 14, DEX 18, CON 11, INT 16, WIS 12, CHA 13.
There's quite a few issues and quibbles to be found here to be sure. One that jumped out at me is non-channeler Lan having a 20 (!) Charisma--higher than anyone except Rand. I mean, Lan's great and all, but wow what. Also I do not 100% know why Dain Bornhald got a stat block while lots of other people didn't: I seem to recall he was involved in the "starter" adventure plot somehow, so that's my best guess. Still, it didn't actively annoy me to the degree that the Star Wars d20 gamebook did in this area...
ETA: Oh yes, and in terms of level, Rand is 19th (with like five different classes), Lan and Fain are 16th, Mat, Perrin, Egwene, Nynaeve, and Moiraine are 15th, Thom is 14th, Aviendha and Elayne are 13th, Dain is 10th, and finally Min and Loial are 9th level (and the only single-classed folks aside from Fain: all three are "Wanderer" class characters--who are kind of like Rogues, with lots of skills in-class, 8+INT points per level, good REF saves, and a Sneak Attack feature, albeit a muuuch weaker version of the 3.X Rogue's).
It's not a bad book at all IMO, though obviously it would require some amount of translation for use in 3.5 or PF campaigns due to being constructed by 3.0 rules, and I haven't read it too closely. ...probably also not easy to find.
Wellll...There may be an effort, but it's pretty poor in 3.X (including PF). An intelligently-played caster is going to be more effective in more situations than a non-caster, and would probably just steamroll a non-caster in a direct fight, just as a channeler would. Spells are just so versatile, and there's a good number that can end encounters on their own. The "per day" thing seems like a balancing factor (in comparison to all-day channeling) but really...isn't, most of the time.
Also, heh, I bet you're right in regards to taking many game groups and putting them in a fantasy series plot: you can't expect them to follow the plot by any means.