Since the Super Bowl era began in 1966, the NFL (using this term for both the AFL/NFL and AFC/NFC eras to designate all teams) has expanded from 24 to 32. I am using current franchise names. During those years, the following teams have switched conferences:

AFC > NFC: Seattle Seahawks
NFC > AFC: Cleveland Browns, Indianapolis Colts, Pittsburgh Steelers

But what if these teams never switched conferences? Granted, the NFC was overloaded in size compared to the AFC which was a reason for the shifts but let's see how realignment might've played out.

I'll make the assumption that the goal would be for even numbers between the leagues so the AFC would've expanded first. After they reach equal numbers, the conferences will expand as they did in our timeline.

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1966 Alignment

AFC (9)
Eastern: Buffalo Bills, Miami Dolphins, New England Patriots, New York Jets, Tennessee Titans
Western: Denver Broncos, Kansas City Chiefs, Las Vegas Raiders, Los Angeles Chargers

NFC (15)
Eastern: Arizona Cardinals, Atlanta Falcons, Cleveland Browns, Dallas Cowboys, New York Giants, Philadelphia Eagles, Pittsburgh Steelers, Washington Commanders
Western: Chicago Bears, Detroit Lions, Green Bay Packers, Indianapolis Colts, Los Angeles Rams, Minnesota Vikings, San Francisco 49ers



1967: AFC adds New Orleans Saints for 10
1968: AFC adds Cincinnati Bengals for 11
1976: AFC adds Seattle Seahawks, Tampa Bay Buccaneers for 13
1995: AFC adds Carolina Panthers, Jacksonville Jaguars for 15
1996: NFC loses Cleveland Browns for 14 but adds Baltimore Ravens for 15
1999: NFC readds Cleveland Browns for 16
2002: AFC adds Houston Texans for 16

Current Alignment

BAL

AFC
East: Carolina Panthers, Jacksonville Jaguars, Miami Dolphins, Tampa Bay Buccaneers
North: Buffalo Bills, Cincinnati Bengals, New England Patriots, New York Jets
South: Houston Texans, Kansas City Chiefs, New Orleans Saints, Tennessee Titans
West: Denver Broncos, Las Vegas Raiders, Los Angeles Chargers, Seattle Seahawks

NFC
East: Baltimore Ravens, Cleveland Browns, Indianapolis Colts, Pittsburgh Steelers
North: Chicago Bears, Detroit Lions, Green Bay Packers, Minnesota Vikings
South: Dallas Cowboys, New York Giants, Philadelphia Eagles, Washington Commanders
West: Arizona Cardinals, Atlanta Falcons, Los Angeles Rams, San Francisco 49ers

I think for the NFC at least, the "4Cs" might still be used for the division names

Century: Baltimore Ravens, Cleveland Browns, Indianapolis Colts, Pittsburgh Steelers
Central: Chicago Bears, Detroit Lions, Green Bay Packers, Minnesota Vikings
Capital: Dallas Cowboys, New York Giants, Philadelphia Eagles, Washington Commanders
Coastal: Arizona Cardinals, Atlanta Falcons, Los Angeles Rams, San Francisco 49ers

That makes sense!

What if the NFL had pushed 3 of its 4 newest teams to AFC upon the merger:

AFC East: NE, Buffalo, NYJ, Miami, Cincinnati
AFC Central: Atlanta, NO, Dallas, Houston
AFC West: KC, Denver, Oakland, SD

NFC East: NYG, Philadelphia, Washington, Baltimore
NFC Central: Pittsburgh, Cleveland, Detroit, Chicago, GB
NFC West: LA Rams, SF, St Louis, Minnesota

1976–Seattle (NFC West), Tampa Bay (AFC Central)
1996–Carolina (NFC East), Jacksonville (AFC West)
1999–Cleveland (NFC Central)

By the 2002 reorganization and the introduction of the Houston Texans, the league looks like this:

AFC East: NE, Buffalo, NYJ, Miami, Cincinnati
AFC Central: Atlanta, NO, Dallas, Tenn, TB
AFC West: KC, Denver, Oakland, SD, Jacksonville

NFC East: NYG, Philadelphia, Washington, Indianapolis, Carolina
NFC Central: Pittsburgh, Baltimore, Detroit, Chicago, GB, Cleveland
NFC West: STL Rams, SF, Arizona, Minnesota, Seattle

after the reorganization, it looks like this:

AFC East: NE, Buffalo, NYJ, Cincinnati
AFC Atlantic: Miami, Atlanta, TB, Jacksonville
AFC South: NO, Dallas, Houston, Tenn
AFC West: KC, Denver, Oakland, SD

NFC East: NYG, Philadelphia, Washington, Carolina
NFC North: Detroit, Chicago, GB, Minnesota
NFC Central: Indianapolis, Pittsburgh, Baltimore, Cleveland
NFC West: STL Rams, SF, Arizona, Seattle

In the AFC, Jacksonville is the obvious team to boot from the West. There’s a strong desire to put the new Houston team with the old Houston team (Tenn) and their instate rival Dallas for which they’ve had a heated rivalry since the merger. It’s either Miami or Cincinnati that’s getting the boot from the East and by booting Miami the league is able to unite all 3 Florida teams plus Atlanta into one division.

In the NFC, Minnesota at last escapes the West division and gets to play with its old rivals. There’s league, faced with moving Carolina or Indianapolis out of the East decides on creating a division that includes the New Cleveland team, the New Baltimore/Old Cleveland team, and the old Baltimore team all together and round it out with Pittsburgh who dislikes pretty much all of them.

With the NFC being more old guard and the AFC the new guard, the AFC has a much stronger Southern presence while the NFC is Midwest heavy.