Well in general when you change a static objects orientation, or scale, you will in most cases have to rebuild the lightmaps as they are no longer valid so if you go that way your probably going to run into a few unexpected problems. Also changing the relative scale in any 3d application usually needs to be reset as most real world lighting models takes the local scale of the object and seeds the rendering requirements off of the relative world scale of the object. So no not a good idea to mess around with scale as to world map objects.
Skeletal models on the other hand are dynamically light and much easier to scale the character up and down via the root as well all things connected to the character will inherent the change, like animations.
