The problem with the loaded media approach is they cause a big problem; players abandon games when they start looking too samey. When each explosion has the same identical chunks as the previous ones, something is wrong.
I think you're better sticking to this approach. There is no reason you can't make several versions of the same object with different breakable parts for some variation. For realtime use, the method you're suggesting will be slower than a week in the jail unless your meshes are very simple.