So we'll have four (former) BCS bowls.
One scenario has those bowls hosting the playoff games on a rotating basis prior to a plus one, although there are still issues to be worked out - i.e., Rose Bowl. Most years, the playoffs will be the champions of the Big 4 conferences, with an occasional upstart taking one of the spots. Here are the options I see:
Rose Bowl
B1G vs. Pac-12 conference champions (on years it's part of a playoff)
B1G or Pac-12 conference champion vs. SEC/Big 12/other (on years it's part of a playoff if they lose their exclusivity)
B1G vs. Pac-12 (on years it's not part of a playoff - usually runners-up playing, sometimes a conference champion)
Sugar Bowl
SEC vs. Big-12 conference champions (on years it's part of a playoff)
SEC or Big-12 conference champion vs. B1G/Pac-12/other (on years it's part of a playoff)
SEC vs. Big-12 (on years it's not part of a playoff - usually runners-up playing, sometimes a conference champion)
Fiesta Bowl
SEC/Big 12/other vs. B1G/Pac-12/other conference champions (on years it's part of a playoff)
Matchup of 2nd choices of SEC/Big 12/B1G/Pac-12 &/or champions of ACC/BE (inc. ND)/MWC/CUSA (on years it's not part of a playoff)
Orange Bowl
SEC/Big 12/other vs. B1G/Pac-12/other conference champions (on years it's part of a playoff)
Matchup of 2nd choices of SEC/Big 12/B1G/Pac-12 &/or champions of ACC/BE (inc. ND)/MWC/CUSA (on years it's not part of a playoff)
I guess that the Fiesta would keep its both of its options open in non-playoff years while the Orange might want to lock down the ACC champion for one spot against a team TBD. So the ACC would be guaranteed a major bowl every other year at a minimum and more if the champion is in the top 4.
Then it gets tricky if you look at potential agreements that could be made for years depending on which bowls are hosting playoff games. You could align the Rose/Fiesta and Sugar/Orange to alternate playoff/non-playoff years, with the non-playoff bowl providing a home to the Big 4 runners-up (or non-playoff champion). That would pretty much put a dagger in the other conferences.