Mob of the Dead is just fine in my opinion; but in fact most people on here(or at least I see a lot of threads about it) think it's too easy the way it is now with the golden spork and hells redeemer.
The reason Mule Kick is absent is because it's completely unecessary; if you get the redeemer and the spork early on you rarely have to fire your gun(unless you're about to get pinched and already threw the redeemer/too many to spork your way through)
besides that, when the golden spork and most weapons(packed) stop working as effective killers we have the redeemer and traps! in fact, to get to 100 on this map all you really need is Jugg, Hells Redeemer, Shield, and a shitload of points earned from sporking until 34. All you do is run back and forth from the cafeteria to the wardens office, setting off the traps each time you arrive and shoot at the train to make points and throwing the redeemer(late in the game it is the only thing that can clear rooms besides the blundergat which will eventually only make crawlers to my knowledge(if this is incorrect I apologize, not a personal fan or user of the blundergat then again I am a self aware point-ho)
Mob of the Dead works for me the way it is but at the same time there's absolutely nothing except maybe flopper in place of deadshot that needs to be added or changed about this map.
My complaints with MotD are the lack of access to the island of Alcatraz, while the whole island is present you can probably only explore maybe 40% and that is being generous. Personally i would scrap the golden gate bridge(I'm sure they could've figured out somewhere clever to put the pack a punch on a giant prison island....)
But even still, I thoroughly enjoy this map as is and encourage that treyarch keeps moving in the right direction with this big, legit zombie maps. and by legit i mean it doesnt take 1 hour to get the game going