The experience in the display when you kill a monster won't change, but the experience you do gain WILL change.
Just check, you'll see a discrepancy between the hero (or DK) who has the wisdom skill and the one who doesn't.
The extra experience you gain isn't really that much, it won't help you gain more levels (well maybe one or two) by the end of the game, but it will help you level up faster...
