I'd like to see an affluency or wealth mechanic introduced. Each village would be poor, standard, or wealthy.

Wealthy villages Wealthy villages would spawn 10% of the time, and would be characterised as a village that's doing well - they have resources, protection, and thriving farms.

• A resident iron golem would be guaranteed to spawn.
• Farms would be larger and more established, with cobble walls often surrounding them to protect the crops. In the largest villages there may be a couple of cows or pigs in a small pen.
• The paths would be paved with stone slabs, and there would be a few fence posts with glowstone on them forming lamps.
• These are successful villages, where villagers have gone out and accumulated some resources. Somewhere in the village will be a small 'storage' building, which contains the villagers haul - they'd typically have 6-8 logs or bark blocks piled up, a couple of hay bales, perhaps some coloured concrete or polished andesite, and occasionally something much rarer - a few gold blocks, quartz blocks, or lapis blocks.
• In the blacksmith, there would be a furnace holding 10-20 coal, or rarely a lava bucket. A new anvil would be on hand.
• In buildings, most floors have carpet on them, and some walls will have a painting on them. Chests would spawn with reasonably good loot. Some buildings would spawn with a small fenced in garden, with some ferns or flowers.

Poor villages

Poor villages spawn around 20% of the time.

• The building floors are dirt, the farms small and sparsely planted with crops.
• Higher chance of nitwit villagers spawning. No chance of a golem spawning.
• The blacksmith has a broken anvil.

Standard villages would be somewhere in the middle, 50% chance of a golem spawning, if they have a 'storage' structure it would be far less loot-worthy. Standard sized farms with no cobble walling, no animals in the pen.

I'd also introduce some variants to add life to the game:

Travelling merchant village A small isolated hut out in the middle of nowhere, with straight-ish parallel tracks of path blocks outside. A donkey would be leashed to a fence post outside. Inside would be a merchant with a really good trade.

Exiled nitwit village 2 or 3 dilapidated houses with nothing of value, just a few nitwit villagers.