To the OP, Roman sounds like a very good fit with EJ as QB and Ryan as HC. I love running plays and Buffalo is - weather-wise and conference-wise - a good place to pound the ball and control the clock. Combined with a superior D, this kind of approach makes total sense. I'll bet Fred Jackson wishes he was a few years younger, but Boobie Dixon might be just what Roman needs. Spiller will likely be allowed to leave and they'll probably draft a new RB along the lines of Gore.
Compare this scenario with what Hackett and Marrone tried to do and it is a big upgrade. Even with the same Olinemen. (Will be interesting to see if they develop Richardson into a good starting guard, but I expect they will.)