I had 2 guys standing on even ground. Other used taunt and shieldwall and other just skipped turn. Orc attacked the one who didnt use shieldwall. So yes, taunt is useless as far as I know.
I believe taunt just makes nearby enemies attack, but does not force them to attack a specific person. This is useful if you want to get through shields, but since we can split shields, it’s not overly useful imo.