KeyerSoze: AI magic sort of work like artillery. In that video you linked the enemy is all infantry charging slowly and in a tight group. That is the easiest form for your channellers to attack. Armies will mostly spread out and thus your magic attacks will miss a lot of the time and hurt individuals instead of groups. If enemy army has cavalry they will be harder to hit and reach your channellers faster. So for me channelling is not OP in all scenarios and you will need clever use of infantry and cavalry to survive. I'd say it is stronger in the books than in the mod. However, if you choose to become a channeller yourself you will become like immensely powerful rather quickly. You will shoot much faster and use the right magic compared to the AI.
Earl of bronze: Not entirely sure what you mean. You put the folder into the modules folder in Warband.