Not sure they need a buff, but, imho, some balancing regarding iron as a building material might be needed. For me black metal and silver is more abundant compared to iron. I can get iron, but it will be a bit of a project/grind. More so than getting black metal or silver, so using iron as a building material isn't prioritised. Using it in poles should perhaps be cheaper, if possible. I've played over 250 hours, done all bosses and built quite a lot, but have yet to use iron poles. They've just not felt worth grinding iron for.