Very nice Modular Pawn System. The addition of a interface to a GUI is an excellent feature. There are several modular pawn/character customization systems (1,2,3) in development, each with its own cool features.
However, I believe the factor that will add significant value for the community is… Asset Supply. The UE4 Modular System with a continuous supply of a ready-to-use interchangeable Parts, will establish The Standard. Have you considered collaborating with Artists to supply the system with modular interchangeable assets?