Map editor is coming in the next update. It will be more a park editor where you place obstacle on a flatground. I want to add more obstacle and maybe different layout in future update.
I did have a replay in the game at some point and was having something functionnal but always got problems with the end result. I will take look after the editor to try to bring back replay without any bugs.
About the community submitted, it's something that could be very cool and wish to have that for the park editor too!! problems is I don't much about server and online stuff in general. I will take a look and might need to research more on it, but can't promess anything since I don't know what it implies.
So for right now, park editor is the priority and should take me most of my time.