Blunt weapons are generally considered underpowered compared to their bladed counterparts. Yes, they have more durability, but you'll need it because it takes so much longer to kill with them than with a blade. The knockdown, while far from being useless, pales in comparison to outright killing a zombie. Sometimes in a single swipe. And (re)dead > knockdown any day of the week.
Some have suggested majorly increasing the damage done to downed enemies to the point where it's almost a guaranteed kill in 1-2 hits (so as not to negate the usefulness of downed finishers) and others have suggested to increase the damage done to Freaks. The last suggestion I heard was to allow blunt weapons to hit multiple enemies at once with each swing. Giving it the same sort of crowd control the special attacks get. Any combination of the above would work, or some new idea from the minds at UDL. But please buff.
Note: BUFF. Don't nerf Blades.