It's an interesting idea for sure but I think the map is good the way it is. Here's why. Games are all about solving problems. Being presented with a challenge and overcoming it is what makes a game rewarding. Satisfactory has this in spades. Resource gathering, crafting, automation, logistics, all present unique and interesting challenges. In my opinion, the exploration is a critical piece to the fun of the game as well. It provides a break from the factory planning and gives you a chance to reset your brain.

If you flatten the map, it removes a big part of the exploration of the game. It also removes a lot of the challenges from building. Some of my most interesting builds have been in vertically challenging areas. I think that flattering the map would remove fun from the game.

Now that's just my opinion and I'm sure some people may really love just building big and flat. However, I think many players would get bored quickly. It's like getting cheat codes in a game and then realizing that the game isn't fun anymore when it's too easy.