In the game currently there are seven types of Special enemies;
Gutter Runner, Ratling Gunner, Warpfire Thrower, Poison Wind Globadier, Packmaster, Lifeleech Sorcerer, and the Blightstormer.
Each of these enemies falls into one of two (or even both categories); disabler or area denial.
But are those the only enemy types that could work in the game? I imagine the devs have probably experimented a lot, but I wonder if those are the only two options? Could we not have enemies that do other things?
The first ideas that come to me are enemies that buff their nearby allies, and enemies that debuff the players in some way. Finally it occurs to me that we could have pure combat-oriented specials; unlike the elite enemies we see around the map, these enemies would come from off-map and attack the player in a more clever fashion than how most elites just run straight at you.
Nurglings (debuff) - Nurglings would actually be a collection of several small Nurgle demons, just under the height of Slave Rats, who run at a player and attack their heels. This does minor damage even on high difficulties, but they can move through hordes freely (their grubby cackling announcing their presence), and heroes they attack are slowed in the same way as when standing in Bile Troll vomit.
Nurglings would break the mold for most enemies because they cannot be sniped with precision weapons easily, being a group of cackling little monsters. Instead, shotgun-type weapons, or CC melee weapons (like great swords) would be most effective at clearing them out.
Chaos Hound (combat/anti-ranged) - A mutant, resistant-type demon hound that is exceedingly fast - and worst of all, dodges projectiles very effectively. When projectiles are launched at it, it will jump quickly to the side and take no damage - it can’t dodge bombs, and precisely timed salvos from multiple heroes can pick it off, but the most consistent way to kill it will be with melee attacks, while dodging its telegraphed bites and slashes.
This will help vary up gameplay by forcing a melee response from players.
Censer Bearer (combat/area denial) - A Plague Monk with a toxic flail that he spins in a circle, pushing back and damaging players, but also creating a toxic cloud like a poison wind globadier, but only around him (to which he is of course immune). High health on this one, and resistant to ranged fire makes him a combination damage dealer and area-denial enemy, who can also hide within crowds.
Fangleader (combat, buff) - There’s already a Stormvermin Commander in the files - why not make him a proper Fangleader who gives some kind of buff to nearby enemies? Put a standard on a pole from his back to make him stand out more, and perhaps he makes enemies tougher or slightly faster or more resilient - he himself would have the same attacks as a normal Stormvermin with a Halberd, but have more health (maybe around 60 on Legend, while regular Stormvermin have 39). However, he’d be a double-edged sword, as killing him could cause other Skaven to become panicked or at least stunned, making him a vital target to kill.
Curse Sorcerer (debuff) - Another kind of Nurgle sorcerer who would target a hero or area of the group and debuff players in the area. The only kind of debuff I can think of that wouldn’t just straight suck the fun out of the game would be a damage debuff, so you can still move and attack, but you deal a percentage less damage per hit. This would make him a pain, but not a game-ending problem. Slowness or taking more damage feel a bit too much. Perhaps the curse could also reduce max health like when a grimoire is picked up (until the sorcerer dies or the curse wears off).
Bloated Zombie (disabler) - A fat nurglite who is swollen with infection and flies. It tries to sneak up on the players and burst, dealing damage and releasing a cloud of flies that attract on the nearest player, disabling them - like the flies in Burblespue’s fight. The flies don’t last indefinitely so it’s not a full disable, but do render the player vulnerable for a period of time.
Just some random thoughts. I know other popular ideas involve Warplock Jezzails - and while I think they’d be interesting, I think it’d be really hard to implement them in a way that would add fun to the game. I feel like they’d work best in some kind of map designed around them, where the heroes have to move between cover to avoid getting picked off.