From a Cleveland perspective there could be no better trio to share a division with - their rival for the state, their closest geographical rival (Cle-Pit is a more serious rivalry, historically, than Cle-Cin) and the team that "replaced" them, under their "former" owner.

As with the north, there are a bunch of rivalries preserved here. As far as geography goes, Miami is the arch-rival of the Jets, while they retain the geographical rivalries with NE & Buffalo. Indianapolis was only the odd man out, as was Tennessee in the North. In both cases, if you HAD to cut one team from the division to get them down to four, the ones that left were the least disruptive to rivalries. SOMEone had to occupy the new division after all, and they could not simply cram one full of expansion franchises and present it as a reasonable & competitive grouping. They'd have ended up with the situation that exists in the NFC west now, but without even that division's history of past successes to offer hope (they HAVE won six Super Bowls and 10 NFC championships, after all).

Recall, however, that that description applies to your Cowboys as well - the Cardinals were in the EAST until the realignment. And IIRC, didn't five different teams win the old NFC West in the last five years of its existance? If the realignment intended to cure any sort of competitive disparity, it was not in the NFC west, where Atlanta, Carolina, SanFran, St Louis & New Orleans took turns winning the division (and going to the conference championship fairly often, IIRC) over a five year period. As far as Indy & Tenn., it could be perceived as punishment for their movements. The teams that were moved out of their divisions in the realignments were either among the newest teams or teams that had moved. The AFC West kept Denver, San Diego, Kansas City & Oakland (who moved, but at least went back) and jettisoned newbie Seattle, the East kept Buffalo, NY, NE & Miami and ditched the mover. In the Central, they offloaded the expansion and of their two moving teams, retained the one that technically speaking reoccupied an abandoned city, while ditching the one that had most recently moved (the Oilers and Titans played in different cities, though I can't recall who was Memphis and which was Nashville).

The NFC was the same; the East ditched Arizona who had moved, the Central unloaded the newer Buccanneers, and the West kept its two oldest franchises, sending the newer Saints, Falcons and Panthers out. In the case of St. Louis, as with Baltimore & Oakland, you have a moving team that reoccupied an abandoned city staying in place.



An ideal geographic representation would be something like:
AFC East
New York, New England, Buffalo, Baltimore
AFC North
Pittsburg, Indianapolis, Cinncinnati, Cleveland
AFC South
Denver, San Diego, Oakland, Kansas City
AFC West
Jacksonville, Houston, Tennessee, Miami

The East becomes a monster division, the North provides 4 of the last 6 conference champions and the South and West are jokes. Not to mention sacrificing the historic NY-Miami rivalry, and Cleveland-Baltimore enmity.
NFC East
New York, Philadelphia, Washington, Carolina
NFC North
Chicago, Detroit, Minnesota, Green Bay
NFC South
Atlanta, New Orleans, Tampa Bay, Dallas
NFC West
San Francisco, Seattle, Arizona, St Louis
Note that Atlanta or Tampa would work equally well in the East. St Louis doesn't really fit in with any group, but since no one questions a Missouri team in the AFC West, it would do just as well in the NFC west.

Really, the only changes needed to "perfect" the geography is a threeway swap in the AFC and a Dallas-for-coastal-state-team in the NFC. Or you could scrap the conferences and come up with eight regional four-team groupings:

Northeast Division
New York, New York, New England, Buffalo

Atlantic Division
Philadelphia, Washington, Carolina, Baltimore

Southeast Division
Miami, Atlanta, Tampa Bay, Jacksonville

Central Division
New Orleans, Tennessee, St. Louis, Kansas City

Southwest Division
Dallas, Houston, Arizona, Denver

Pacific Division
San Francisco, Oakland, Seattle, San Diego

Old Northwest Division
Pittsburg, Indianapolis, Cinncinnati, Cleveland

North Division
Chicago, Detroit, Minnesota, Green Bay

You can have history or geography. The current set-up does as good a job as possible of giving us both. The history lost in the realignment is minimal, and cross-country travel within a division is likewise minimal. BTW, I note that my proposed geographical lineup would be reasonably competitive this year, though the Pacific would still suck balls, and the Northeast would become a rather nasty one. Aside from maybe the Southwest, every other division has a couple of current contenders.