Finally you can just build with wood, stone, concrete and steel. All the upgrades in between have been deleted, and wet concrete is gone too so less clicking and just build with steel if you want. Nothing downgrades to anything either, when the hit bar is gone the block goes poof. A fairly big change, but now each tier is meaningful and it won't be 1000 clicks to go from wood to steel now.
I liked all the rest of it, but this... pour one out for bricks I guess. I've been saying for years bricks just need some balancing so there's a reason to use them - some scenario where they outcompete alternatives like cobblestone. Instead, they get no attention until they're abandoned/reabsorbed completely.

out:
So the best building system of all time will only have 4 building materials? I would've sooner expected that in Alpha 1, not Alpha 20. Fast forges, instant dry concrete, and deleted upgrades is going beyond simple is great. It means eroding the game's core principle of time management.
I can't tell you how many times I've had to agonize over whether I have enough time to upgrade a wall and have it ready to go for the next horde night. Will plain concrete be strong enough? What will I regret more: not reinforcing it, or that it's still wet in a few places at the stroke of 10 o'clock? Is my scaffolding and technique efficient enough to hit every block with a hammer in time? No? Okay, then which blocks do I
really not want to fail the most? This decision making is what makes building in survival more interesting than building in creative mode, and it seems we're going to lose that.
I would've preferred streamlining the depth, but maintaining or even expanding the breadth. It was neat when you could build adobe cheaply in the desert, because you were leveraging the local materials available. That could've been expanded: cinder blocks in the burnt forest, pykrete in the snowy biome, scrap iron in the wasteland. Remember, the long, unified "1000 click" upgrade path from wood to steel was a more recent addition. You could've kept a short path of [weak material] -> [reinforced weak material] -> concrete -> reinforced concrete -> steel, where wood, stone, and scrap iron are just three of several weak materials to choose from at the bottom of this short but broad upgrade graph.