I think the building system is fantastic addition. That's just what it is at this point though a small addition, I can't wait for mods to expand upon it and as an optional feature as it is now, it's not bad for what it is.
It sort of forces you to be the good guy in settlements though? No real room to make a sort of evil society with how the storyline goes, but again, that's what mods are for. I would loved to have taken the ironworks as my own Forged raider base > = D