I know there has to be a limit in outdoor housing because the area has to load as a whole, but some house styles come with very little adornment (oasis). I started decorating the outside of my house and was very surprised at the low limit of items...I'm just putting in a stone walkway (7 items when it should really just be 1 or 2) and gravel (15 items instead of just 1) and a pond with some trees and path lights...and got about 1/3 of the way done and had to stop.
I'm not asking for a wild limit increase for outdoor furnishings, but doubling it would be a start. And making some changes to certain items would be nice, like stepping stones being more than 2-3 stones when you need 14 stones to go from the gate to the front door and the side yard of the house. It eats up 7 items of the 20 limit just to make a simple walking path this way. Or allowing for different base layers without takin away from the item count (grass, gravel or different sizes, etc), I had to completely scrap the idea that I would be able to put any gravel down since it would take all 20 item slots to partially cover the plot in gravel.