If we could attach event sheets to objects, we could introduce some modularity into construct!
Consider this: I make a car with a turret, but I write specialized code for it in a separate event sheet called "rocket launcher car events". For example the event sheet has a function "shoot" that takes in the target UID and does something special with it, like firing a misile to that target in a randomized spline path. Then I attach the "rocket launcher car event" to the car sprite I create and that's it. Now if I add a rocket car to any of the layouts, it's even sheet is automatically going to "include" the "rocket launcher car events".
I can make many objects with special behaviours and save all of them in a layout, and I can just load that layout whenever I start a new project so that I can access my "library". The possibilities with this approach are endless, and I think this is easily doable without too much change on the existing editor code or features.