Basically, a (simple?) mob and weapon mod centered around Villager infantry. I'm busy learning Java to try my hand at it myself, but since 1.14 will probably be out long before that I'm looking for a person who likes the idea enough to make it.
The mod centers around one mob: the Militia.
Militia are basically Villager soldiers. They wear blue coats (shorter than the regular Villager robes- think the Vindicator and you have the right idea) and white pants. Like the Witch, they have a hat, but instead of a tall witch hat it's a short, wide-brimmed black one. Their sole piece of armor is an iron chestplate. Stat-wise, they have 20 health (10 hearts) and 6 armor (3 chestplates on the armor bar). Like the Vindicator, they tote a weapon; in this case a musket.
Militia soldiers spawn just like any other Villager, being considered to be another career, and count for the population as well. Militia usually amble around during the day just like other Villagers, socializing, but during the night they switch to an aggressive patrol route instead of running inside, walking around the village just like Iron Golems at a slightly faster speed than walking. At any time (day or night) if they detect a hostile mob within 24 blocks they'll immediately attack. If a Villager is attacked they will try to sprint toward the offending mob to engage, just like an Iron Golem.
Militia soldiers will fire their Musket at any hostile mobs (including Illagers). They must spend three seconds to load the musket (in which they move slower and their gun tilts upwards), and will strafe around aiming and shooting if they have ammo loaded. Like a Skeleton they will strafe and try to back off if wounded. They slowly regenerate health when not in their combat state, and when mortally wounded will try to run away. Their Musket is reasonably accurate and deals 7 hearts of damage per shot. Naturally-spawned Militia will attack very unpopular players just like an Iron Golem.
Militia can be created by throwing a Musket to any Villager. The villager will stand still emitting small shield-shaped particles and will become a Militia after 10 seconds. Militia can't be traded with, but created Militia will follow the player around and can be ordered to stand guard (standing still, shooting at any nearby mobs), follow the player and attack hostiles, or just wander around the village and engage enemies like a normal Militia, alternating through these modes with right-click just like with a wolf. The Militia will show what mode he's in with a short chat descriptor (Guarding, Following, and Patrolling). If in Following mode, he will teleport to the player if far away; otherwise he won't teleport to the player.
The weapon used by Militia is the Musket. Muskets are crafted with three Iron Ingots, three Wooden Planks, and a Flint and Steel. They use Cartridges for ammo, which are crafted with one Iron Ingot, one Gunpowder, and three Paper, producing four Cartridges. It has 60 shots worth of durability and can be repaired just like any other weapon via an Anvil.
Muskets start unloaded. To load the Musket, you have to hold right-click. This slows you to sneaking speed and shows the gun pointing upwards. A bar fills up in the Musket's hotbar slot; upon this filling, one Cartridge is consumed, the Musket produces a clicking noise, and it is ready to use. If you look at it in the inventory, it has a tag denoting whether or not it is loaded. Holding right-click aims the Musket forward just like a Bow; releasing right-click fires.
Upon firing, the Musket produces a puff of smoke, an explosion sound (like the old Creeper explosion), and shoots a bullet, which looks like a tiny round metal ball. The bullet travels fairly quickly and has low drop compared to the Arrow. It travels around 40 blocks before it even hits the ground. Unlike an arrow the musket ball cannot be retrieved if it hits the terrain. The Musket can then be reloaded and the firing cycle repeated. The weapon deals 10 hearts of damage per shot.
So that's effectively it. Just two items and one (slightly complex) mob with a patchwork of features from other mobs. If this is at all interesting enough to attempt, please go right ahead and tell me; I'd be happy to see this realized. Thanks!
There are two possible "types" of AI I've been thinking of for the Militia:
Skeleton-style: The most "complex" but cool of the possible AI types. The Militia strafes, runs quickly to defend Villagers being attacked in a village, and acts like a Skeleton in combat (minus the infighting). Basically meshing the Skeleton's behavior with a Villager's.
Simple Ranger: Less complex, could be coded more easily. Just runs if a Villager is attacked and paths to the enemy, then stands still and keeps shooting and reloading. Kinda like the pre-1.9 Skeletons.
I'd be happy with either, but I'd ideally like skeleton-style Militia.