It would be great to be able to build houses or docks, bridges, etc. without getting the message that something is in the way. Often the rocks on the island are what is in the way and preventing the user from placing a foundation or floor. Currently we have to work around this by looking around different directions quickly and then placing the item in the brief half second before it turns from blue to red.
The main motivation for me is I like to build short bridges over tight inlets. I always try to get the ends to be partially in the sand so I can walk onto them without jumping or building stairs. Often rocks are blocking at some point in the path.
Also if you build a two story house, you get the same message that something is in the way if you try to place a light hook more than half way up the first story wall. You have to destroy the second story wall and floor above the area you want the light hook, then place the light hook near the top of the wall, then rebuild the second story floor and wall as a workaround.
Another scenario is when building houses. You can plan around the rocks mostly, but still sometimes you get a lot of the foundation laid and then can’t finish due to rocks or other objects and have to tear it down and start over or use the workaround above.