I recall being annoyed at the building system in the beginning but I'm not sure why. It's pretty easy once you get used to how it snaps n shit.
I've started my North map base. Moving all my stuff over from previous Ashlands save.
Parts that annoyed me with building when first trying the game was that I could never build the way I wanted to because things kept falling apart. It is never explained that you need stronger supports and you only get them later on. I mean, it is logical and makes sense, but when starting it feels very limited.