My guess would be if we were given the ability to add more than 5 objects, it will/would somehow make the server laggy or unresponsive and that would definitely make the players really unhappy.
Sure, it's annoying and it would be nice to add more objects. Imagine 5 props per players but there's roughly 50-100 players per server so that would accumulate around 250 - 500 objects in the server. Im no server engineer but that would definitely affect the gameplay's experience.
My guess they want to focus on the player's perfomance and limit the object placement but that's my assumption. Take it as a grain of salt.
I think the correct way to improve this is to add the ability to rotate the X,Y and Z axis and bring back the floating object glitch.