I think it has to do with the writers of the story/game (again). Tolwyn makes a semi-appearance in SM1 (on the box cover on the back) and 2, as well as Freedom Flight. His first real appearance is in WC2, where he is distrustful of Blair. However, he's forgivably hateful of Blair, since hardly anyone else seems to trust him. After Blair proves himself at K'tithrak Mang, Tolwyn seems to trust Blair, an almost fatherly figure. ER and FA reinforced this idea with Tolwyn and Bondarevsky. When WC3 came out, we had a new writer of the script who oversimplified many things. This, combined with McDowell as Tolwyn (How could McDowell NOT play an insane guy), turned him into a more three-dimensional character. The WC3 novel suddenly notes this change in character. This set the stage for WC4 and his demise.
Again, with all of the various people who have meddled in the WC field, it's only natural to see these inconsistencies.