Being able to place items and building pieces without line of sight is the reason why you can still place explosive jars through ceilings. You can imagine what that means for someone on a PvP server …
Sorry if it sounds harsh, but PvE is a niche way of playing. Like reanacting the battle of waterloo with Barbie dolls.
These small things have a really big impact on PvP balance. Even when tiny things like the hatchdoor where introduced, it opened up some serious exploits such as undermeshing, jump exploiting and server lagging and even building flying bases. Not that I don’t want the PvE community to play around with these things but the price to pay was rly too big. We had an exploit rampage for months in exchange for a decorative item.
edit: all exploits mentioned above are fixed. I am not explaining or discussing how to exploit the game.