The videographer did a special on the evolution of the PDW. If I am to believe him this all came about based off of combat studies and the need for individuals to have a close quarter weapon that is easy to wield,

I'm not convinced a PDW is needed in close quarters.

Having said that I do think the shorter platforms are nice for CC or packing away when needed but the last place I want to be is confined to a building/bunker because I am more geared to open spaces. Not saying that I couldn't get out of a wet paper bag, but I would rather have a pistol or shotgun for tight spaces.