I would like to see more infected types in DayZ. Variety is Key.
Here is my list that would fill the gap for this suggestion

New variant of Infected Firefighter wearing Black Firefighter Gear instead
Historical variants - Infected spawns at castles, variants could be knights, bowmen, swordmen, kings, queens, or jesters.
Amusement variants - Infected spawns at luna parks, variants could be clowns, mimes, different types of amusement park workers and guests
New NBC Variants - Variants can be wearing yellow or green, they wear special oxygen tanks and a special helmet for the use of the oxygen tank.
New Military variants - these can be more U.S. soldier types, and local soldier types. Could add all types based off the current clothing types that are in the game {BDU, CCU Woodland/Desert, ETC}
New industrial variants - these could range in as lumberjacks, demolitionist, and/or contractors
New City variants - infected ranged in wearing different clothing types