If Tasha had stayed it would have made sense to make Worf the chief engineer, he was the one main character (minus Wesley who was a kid) who didn't have a defined job and they wanted a permanent chief engineer towards the end of season 1.
Wesley would then fill Worf's slot of helping out wherever he's needed which makes more sense than sitting at the conn if he's supposed to train.
Wesley would then fill Worf's slot of helping out wherever he's needed which makes more sense than sitting at the conn if he's supposed to train.