Newly I read in UA about those Paragon classes and I thought they fit perfectly into the BR system. Naturally there should be created 5 different human paragon classes (brecht paragon for example) with different hightened abilities and different bonus feats. Dwarf and elf paragon are perfect as they are presented in UA, but halfling paragon can be varied. I would suggest granting those shadow world feats as bonus feats for cerilian halfling paragons.