This post will probably end up becoming a little excessive, so I'll try to separate easier/more realistic improvements from stuff that I'd just really love to see.
- Allowing waymakers to dig deeper water holes. Natural ponds have deeper spots that take longer to freeze, which allows water masters a little more time to gather water in winter. A related thing: growing taller trees with "motivate land" and taller rocks/mountains when using Earthquake.
- It might be more due to population creeping up before the first winter than an actual "flaw", but water is scarce, like food, in winter because of snow instead of rain, frozen ponds, and hail. There could at least be a tip about saving up water before winter.
- Golems have no resistances or weaknesses, only a damage type and some health and stat variance. It would be nice to have more differentiation between the golems, especially if more hostile mobs are added with more varied resistances, weaknesses, and damage types. Which reminds me— poison wood golems are a bad choice right now.
- Builders almost never perform repairs if there's construction or building upgrades to do. This could be fixed by adding a dedicated repair job if it isn't possible to just change the basic prioritization of the builder job. Alternatively, one of the golem types (probably wood) could be given the ability to repair all buildings, while the other two act as dedicated tough melee/fragile ranged defenders.
- Diagonal roads. They currently look like a mess, and making the roads zig-zag is a waste of resources and space.
- Pausing during autosaves. The game currently lags during autosaves, which can cause deaths and a loss of essence if the player was holding something during the autosave.
- Building tooltips (other than the ones in the build menu).
- Faster withdrawal of essence from essence collectors. Constantly having to scoot the screen back to the collectors and wait for a recharge is a dull chore.
- Automated creation of new stone and wood resources via motivators, like the Crystal motivator. Alternatively, there could be a "forester" job and permanent stone mines that miners can enter (I think I remember Ray speaking out against this, but it could be made less "artificial" if the mine produces large stones or minecarts filled with non-resource stone that the miners have to break down into regular resource rocks, along with a chance for gold/iron ore).
- Larger maps. I like the size of buildings (they're fairly proportional to the size of villagers, which I like a lot), but a late-game town takes up a lot of space.
- Randomly-generated maps! Given that RtR is based around building up a town and surviving as long as possible, providing randomly-generated landscapes to adapt to would provide potentially endless replay value.
- More biomes with more gameplay-affecting features, like the tar pits and dead trees in Newdragon. The base terrain itself (ex: sandstone, sand, dark green grass, light green grass, dirt) could have more effects on gameplay, like farm production speed, and perhaps more terraforming spells could be added to manipulate that (ex: kill or grow grass to change soil fertility and movement speed).
- A higher-quality food tier. Kitchens could produce "meals" that restore more hunger and provide happiness, but require more time/food to produce and maybe decay. Perhaps this could be designed in a similar way as farms; the chefs could place cooked meals on a table, where they would be eaten or eventually rot and disappear (with no option for long-term storage).
- More enemies, with stronger miniboss/boss enemies appearing very rarely and/or from spawns that aren't dealt with after a long period of time.
- "Caster" job and/or enemy type. Something like a priest that buffs/heals allies while using up essence (perhaps via a staff that he/she has to craft) or a wizard that uses AOE attacks with magic/elemental damage types. Crylithium could be refined into a magic ammo instead of having a "caster" use essence. The hostile equivalent could be that same wizard, or, better yet, a necromancer that resurrects corpses and uses cold/poison ranged attacks.
- A "church"/"temple" building that specifically deals with corpses. This could be the source of the villager "caster" job. It could have a graveyard where corpses are buried for bonus essence (slightly more than letting a body rot or poking it until it disappears, but less than dropping a live entity into a Cullis Gate), and villagers could visit it for a happiness boost.
- More visible villager equipment. Visible shields, tools (not just the generic grey rectangle), weapons, armor, and helmets. Visible armor might cover up the colored shirts of different jobs; this could be counteracted by providing more colors on the rest of villager sprites (gloves, shoulder areas, shoes, pants).
Thanks to anyone who actually read all of this!