Something positive first. The game is extremely fun and satisfying. I enjoy it immensely. Despite minor performance issue and bugs I don’t really have any big issues I haven’t mentioned already, others haven’t mentioned already etc. Looking forward to full release, you did an amazing job on this one.
The terrain tool needing an improvement isn’t new. However it frustrates me so much it’s without exaggerating - THE achilles heel of the game in its current state.
The flatten ground has a huge issue. Other than taking way too much work (maybe lower %work force needed per townhall tier?). Or add an option to quickly elevate ground for 1 stone and 1 wood per 8 tiles, drastically lowering the time for it costing resources.
Anyway… main issue is the averaging out of terrain. Say you want a tall mountain with a steep slope straight down. This is managable, but it can take 2 ingame years or 20 depending on the existing terrain. It is too dependent on existing terrain being favorabe. As you have to select the upper side elevation with just a small line of 1 times X squares to “hook” it up. Do the same at the bottom.
A more grievous problem was something I found out today. I wanted a tall but not thick mountain as the gate to my town. So think a tall steep mountain. I basically wanted to make a tunnel through it. Sort of splitting the mountain in half. With a passage way on fround level and steep 90 angle. So straight fall down from the top if villagers could express their pain with the terrain tool and jump).
The terrain tool, for flattening ground, is bad. Saying that is beating a dead horse and if that was my only issue I wouldn’t create this massive wall of text complaining about it 
But for terraforming the map by say… create super steep straight up areas. Rapidly elevating just a few squares drastically. Like if you want to build a non-optimal but RP themed residential district in a “city of clouds” on the ledge atop the mountain. It is absolutely possible. But it takes like 10x the time it should.
Today I played 8 hours. After getting my city to a self-sufficient relatively small size which could support 15 builders indefinitely. 7 of those hours went into making my "tunnel through the mountain. It was a hundred times harder than it needed to be. Extremely inefficient, and very boring.
It basically burnt me out completely trying to fight the terrain tool.
So yeah. Loving the game so far, very promising. Taking a break for now. I just really hope the terrain tool gets some serious improvements. One change I think should be added is the ability to raise or lower ground directly (no averaging out). This would sort most of the problem.
The issue isn’t difficulty. I made a colony which sustained itself indefinitely with 15 builders “free” for 24/7 elevating work. For 7 ingame years. I used a timing window strategy to give me all the time in the world to finish elevation work before making my mountain city. But it was one of the most Zzz things I’ve ever done in a game.
Like valheim. Straight up raising or lowering the ground directly, and quickly, needs to happen so we can terraform more efficiently. Even just wanting to flatten an area in a vanilla fashion can be an uphill battle with some guesswork.
That’s pretty much it. Looking forward to full release. I pray the terrain tool isn’t “unfixable” from a coding or technical standpoint. As for balance many solutions are possible. Just for the love of God stop it from being such a slow, boring and frustrating chore! 