Zombies should be deadlier!

When I think of minecraft zombies they don’t look quite tough to take care of.
It can be better if they have a more realistic effect in movement and textures and zombies should have different types of skins as one skin for zombies looks plain and not that fun.
Zombies should be in groups!
Zombies should sometimes have one less arm or leg. This should even change thier speed and damage.
And finally if a zombie kills you the inventory the player had dropped should remove all the rotten flesh and some other items.