Some of the new furnitures have huge hitboxes, making them impossible to place close to other objects. The Belfry likely has the biggest box of them all, reserving a walkway as wide as the steps on 3 out of the 4 sides. Pictured below I've placed the belfry as close to the walls as it will allow me, and raised flowerbeds at the edge of the hitbox on the other sides to showcase how wide the dead space is. Basically, had the steps not been there, it would've had an equally massive gap on all sides. 

Upon further investigation it seems their hitbox is the same as their roof, because the gazebo has a pretty large hitbox too although not quite this bad. Compare it to trees which can have their crowns/leaves/branches hang over the edge of the perimiters to the manors.

With this hitbox, if one would like to place the gazebo in a corner, slightly rotated (one click), this is how huge of a gap would be left behind, where no other items can be placed apart from in the very inner corner.

Some of the plants also have abnormally large hitboxes. Both azaleas for example.

Sometimes patches also become untargetable. This is an issue that has existed since at the very least the release of the manor in heidel, where sometimes you can't target items unless you look at them in an awkward angle like from above or through a window. With this manor I've also experienced an issue where everything in these patches (part of house with balcony), I can no longer select the furnitures at all regardless what angle I look at them (believe me, I've tried for hours lol) Only way to access those items now is to find them in the list, stash them to the inventory and hope it's the right one.

I guess more than anything else, this is the single most important issue that's holding Black Desert housing in general back; Furniture hitboxes should be basically completely removed. 

I wish PA would look at some other games that have done this. Two examples are Everquest 2 and Elder Scrolls Online. These game show how amazing it can be to decorate when there are no/limited placeable hitboxes, and both have significant communities solely focused around home decorating/building as a result. And there are plenty of other examples of games out there too.

There is no reason Black Desert cannot also become a great game in this regard, and arguably PA have already done hardest part; by providing us with so many furniture items in game already. They just need to fix a couple of glaring issues, and housing here would be amazing.

Isn't the limit at least partially because of the competition for top furnishing points to get at the investment banks and special nodes? Or maybe not even that, just for bragging rights, or just to see the numbers go up.

But the manors don't count for that, so what's the point of limits there? Of course, it could be an implementation detail that they find difficult to work around.  If so, one solution for that is to just use a tiny hitbox for everything.

It also sounds like there are other placement bugs beyond that too.  

This would be my dream! I've seen so many screenshots of people in the KR server who've managed to essentially cancel the hitbox by glitching furnitures together, enabling them to create completely new furnitures and I'm so jealous. I wish I could figure out how to do that but from what I understand, it's a glitch they guard heavily for obvious reasons. The house aspect of BDO is one of my favourite parts of the game (spend billions of silver and countless hours in my various homes xD), but it could definitely use some improvements.