OK, using Malleble VIs is cool. Imaging being able to not only wrap code around a variable datatype but wrapping an object around a variable datatype.
I personally have quite a few classes which do pretty much exactly the same thing but which only differ by the precide datatype contained within its private cluster. No changes in the number of elements, no changes in methods, only the datatype of the specific data.
Obviously, the datatype would have to be compatible with all methods and VIs of the class which use that data field or we would have broken code.