with a blackmane great pack you get fear and furious charge for the entire army. you don't get that with wolves unleashed. also to run the great pack you need to be playing 1850 or more. anything less you really have to shave points off.
i would still keep the banner because the more units you can drop next to the banner the better. with the counter attack and counter charge rules that will add up to a lot of extra attacks really quick. in short death by numbers.