Hey, I would just like to say at first that I hate unity (and .NET aswell) so I have a bit of a bias towards every other engine that exists and doesn’t use .NET, but I have my reasons for that.
Ok, so this post will be a list of reasons why UE4 would allow unturned to branch out and become a much bigger (and probably better) game!
Reasons for UE4:
Better performance - While it is well known that C++ can be faster than C# when done correctly, the way UE4 is written helps you to make code that runs well. For example, the way to call their APIs is through a bunch of macros, so alot of what you are doing is handled by the engine rather than you, while still giving you full control if you wanted. Also, blueprints are much faster than C# due to them statically compiling, and because they are directly translated to C++. Also, I have found that using the exact same shaders on both UE4 and Unity leads to UE4 having better performance. This was tested on my main PC (I had to sell my old one) that has integrated graphics at 2ghz CPU. 2 ghz!!!.
Better mod support - Epic Games has been known to work with games that they think have potential, for example PUBG, Squad and ARK (back when it was much smaller). They have made modding SDKs for games that allow you to do anything you can do with blueprint, and that is almost anything. Currently in unturned, adding new weapons or vehicles is making a model and editing an XML file that specifies how it should act. This is pretty bad for modders that want to add more functionality. I mean, sure, Rocket exists. But with rocket you can only do server side scripting, and it is very limited. If Mr Great Lord Papa Nelson were to contact Epic Games, then Epic Games could help him set up a modding SDK similar to that of ark where modders can do anything that the game allows for and more!
Any scripting language - Because C# is an interpreter (Or JIT compiled, idk) language, using another scripting language that isnt integrated with .NET will lead to worse performance. With UE4 + C++, you could use ANY scripting language because C++ is statically compiled. Even languages that don’t work with C++ natively (I’m looking at you Dyon), could be implemented using pre-compiled libraries (Dyon uses Rust, and Rust can make libraries). You can even use C# via Mono, as that is the approach that Garry Newman + Facepunch took with their new sandbox game.
Anyone can get access to UE4 source code - While this is alot smaller, if Nelson wanted to modify the engine in any way, he could because - if you link your GitHub account with your Epic Games account - you can access the UE4 github repo.
So, if anybody would want to say how the devil spawn that is Unity would be better, feel free to tell me