If McD's ego s so large that he would forgo the opportunity to work as an offensive coordinator with what is largely considered one of the most dynamic and prolific offenses of not only this period, but of any period......... just so that he could work as an offensive coordinator in a mediocre, ho hum system........ then he is probably not an offensive coordinator we would want.
What NE is doing on offense with the TE position is light years ahead of what the rest of the league is doing. Granted, there are other prolific offenses right now (GB & NO), but they are doing it using an "older" BB model, ala 07 NE or 99-00 StL.
NE is doing things at the TE position that have NEVER been done, and any OC worth his salt should be willing to be a part of that and to help mold/refine it. If it was between being an OC at NE, or a head coaching gig then yeah, I could see him going elsewhere. But for an OC here, or an OC there..... I can't see his ego being so big that he would pass up the opportunity to work with TFB, our OL, TE's, etc..... just because of some BS perception that he's "coming home" in failure.