If you don’t want stronger zombies because they would make you question how they exist without disintegrating, then you should also question how shocker types continue to glow and emit electricity without any means of power generation, how smoker zombies constantly to emit smoke, how zombies are able to return to life an infinite number of times even though body mass is inevitably lost during combat, and a lot more. And if you have already pondered over these questions then you would probably have heard that all of this is hand-waved by the blob entity controlling the zombies somehow providing energy and biomass.
I guess smarter zombies could be a thing, though according to lore the blob is too preoccupied with a lot of other worlds. However, I feel like gun zombies are weird, since the zombies in this game focus mainly on killing as many living things as possible in the shortest amount of time, whereas a gun, despite being a powerful tool for killing, is a product of time and preparation.
If you want to kill people, you can band up with a team of people to slowly hoard supplies to make a Barrett and a few BMG Ball rounds, mark a hidden vantage point with a good view, and kill a few people with a near 100 percent success rate. Or you can just get a machete, take some PCP, and run about, mortally wounding as many people as possible before getting shot down or restrained by the police. I’m pretty sure that zombies would pick the latter, because it costs much less resources and time for a similar amount of dead people.
While a zombie army would be hard to beat, I think an army is usually meant to cripple an opposing country’s military force so that that country listens to the demands of said army’s leaders. The blob wants all living things to be under its control, so a nuke won’t accomplish much, as those killed will probably be vaporized and therefore not suitable for control. Smart zombies could make toxic gas, or an extremely big bloated zombie could just fart, but then again a lot of human survivors have gas masks or at least most people playing this game have obtained one though various means. The blob could take the form of a virus, but apparently it can’t take control of living lifeforms, nor can it act as a fatal poison. A gun and a lot of bullets could work, but people would probably learn to run away from the sounds of gunshots, and again, bullets and missiles are expensive in terms of time, both in manufacturing and safely transporting all of the ammunition. We usually don’t use guns to kill indiscriminately (and when it is, the deaths are often for intimidation), but to solve a specific problem quickly and without opposition. There are probably a lot of other ways of doing genocide while leaving the bodies of the victims intact, but it would probably take time and brain power that the blob just doesn’t have to spare since it is fighting a lot of other battles on different worlds.
However, I think it would be cool if zombies had upgraded versions of their ranged attacks. A corrosive zombie could adapt to have a much longer ranged spit attack, a shocker could create bigger fields of electricity, etc.
