The first thought was to cannibalize the Warriors deck, long sacrosanct just b/c of its win record, and see if the Warrior framework could work in Mardu colors.  Surprisingly not, there were too many white must-haves in the warrior tribe.  Both Mardu and Warriors had a human subtheme however, so the potential for crossover/emphasis was palpable.  Looking for humans brought me to the White Devotion deck.  OK so now I can easily cannibalize that one to keep the Human subtheme in both originals, and I can use the White Devotion to reinforce the Warrior subtheme with a better sense of identity.  Although I would finish the new White Warriors second, having these two as seed material made the final product easy to design.  all it lost was some of the bolster mechanics for some powerful devotion abilities.

   Still focused on Mardu however, it increasingly looked like the boros themed cards were the ones that needed booted.  Too much white if i was going to import the new cards i wanted to add, and 6 of those new ones were now anchors.  enter the rats.  I've never had enough rats for even a half a rat deck.  most the black deathtouch ones weren't appropriate over here.  A lot of the newer red ones however, were actually human creatures that created rat tokens.  that was kinda perfect both thematically and to improve swarming offense.  by this point my average CCM was way higher than the original, so extra lands rounded it out. 

And so 3.3 decks have condensed into 2, both of which I think to be significantly better in quality and theme.  imaginative combos ftw