Just about all of the problem with this is the way that BVE is coded as a whole. This is because Mackoy chose to implement various new functions into BVE 4 which were not present/ differently implemented in BVE 2. In some cases, this would mean the re-writing of large sections of code simply to achieve scenic parity. The best example of this off the top of my head is the way that panels & train acceleration work in BVE 4 as opposed to 2- in BVE 4, the .dll file handles most of these functions, & can be customised nearly at will. BVE 2 on the other hand works within a very restricted set of parameters, and workarounds had to be found to create effects. Therefore, it is easier in many ways to create the same effect in BVE 4.