Changing from the old system to the new system proved to be a very challenging experience, primarily due to the difficult nature of finding information on this system. As the New Input System (NIS) is not standard, there is not nearly as much documentation nor resources to reference.
However, I do see the potential of the system. When the NIS becomes the standard and new developers with little to no coding experience begin working in Unity, the NIS will be a much cleaner transition as much of the programming logic is handled behind the scenes.
My gripe with the NIS is akin to my feelings about Unreal Engine’s “Blueprint” coding; if you are brand new it is an excellent starting point, but if you have coding experience it can be frustrating when you do not know what is being handled behind the scenes. As someone with several years of programming, I like to either handle or view the logic directly; when it is done internally it is not always clear how the program is articulating the desired input.
This isn’t generally an issue for small scale projects or simple task completion; there are hundreds of ways to solve the same problem in both programming and game design. But when intricate systems have to interact across a variety of objects, scripts, levels, etc. it is pivotal that the developer(s) know how everything is communicating at each level. You cannot fix a bug that you don’t understand, after all.
And that’s it. The NIS will eventually become the Unity standard, and is certainly worth learning as it develops and finalizes!