The main differences are:
-- A selection committee will make the decisions.
-- The Big East got put at the kids' table.
-- One of those is a championship game "outside" the six (up from four) member bowl games.
Gee, that sounds kinda like a plus-one. The main difference between this and the plus-one as people understood it was that in the plus-one, two participants would be selected for a championship game based on bowl performance. In this, we already know who the four teams are.
Three contract bowls - contract meaning they have contracts with the various conferences to host their teams - and three at-large bowls are the basic makeup. They haven't said who the three at-large bowls are, but if it's any other than the Fiesta, Cotton, and Peach (the one whose "real" name is a fast-food chain) people will be pretty shocked. What, you expected the Hunger Bowl?
They've also taken to calling the conferences involved the Power Five and the Group of Five, which I guess is because they didn't want to hurt anyone's feelings with Big Five and Little Five. I like Big Five better, it goes with Big Ten and Big 12. The Big Five, of course, are the ACC, SEC, B1G, Big 12, and Pac-12, and congratulations are in order to John Swofford and the ACC prez committee for keeping the ACC at that table when it was distinctly possible we wouldn't be. Bonus: the fantasyland 4x16 model is dead, as if it was anything other than a figment of overactive imaginations to begin with.
A couple of assumptions are going to be made here. One is that the rotation of semifinal hosting means that each bowl gets a semifinal once every three years. I can't imagine the bowls want to be shut out, or in, for too long a period. (The only exception: the Rose might get touchy about not hosting its traditional matchup, and might decide it wants less of the rotation.) I'd also guess that each semifinal will include one contract and one at-large bowl each year. That'll avoid having too much nutty upheaval in any one year. The other thing that does is keep a similar number of at-large slots open every year. If they have the semis at, say, the Orange and Rose, that theoretically means four contracted teams could bogart four of the six at-large slots, and with one more at-large slot guaranteed to the Little Five, that doesn't leave much room for selections. I think they'll want to avoid that.
Each contract bowl in the system breaks down like so:
-- Rose Bowl: B1G champion vs. Pac-12 champion two out of three years, a semifinal in the third.
-- Sugar Bowl: SEC champion vs. Big 12 champion two out of three years, a semifinal in the third.
-- Orange Bowl: ACC champion vs. highest-BCS-ranked team from the B1G, SEC, or Notre Dame, two out of three years, and a semifinal in the third.
Both the Orange and the Sugar will take teams from their contracted conferences in the event their league champions play in the semifinals. This is a change from when the bowls merely got first pick when they lost a team to the BCSCG and the conferences weren't guaranteed to have their second-place team go to the BCS. In this way the Big Five have managed to consolidate their grip on power as a result of Little Fivers pushing for more influence. Nice going.
The Peach Bowl, the Cotton Bowl, and the Fiesta Bowl will take what the selection committee gives them. The Cotton Bowl is in the best position of the three. Why? Because the Big East and Mountain West are the two most likely conferences to place someone in the Little Five guaranteed slot. If it's a Big East team, the committee will probably put them in the Peach. If it's an MWC team (or one of the geographically insane Big East ones)** then they'll probably go to the Fiesta. The Cotton Bowl would probably only end up with a nearby CUSA team or one of the Texas Big East teams, and in the latter case they'll enjoy plenty of local traffic. Otherwise the Cotton is likely to find itself hosting SEC teams with a fair amount of frequency.
Each conference in the system breaks down like so:
-- ACC: Champion to the Orange Bowl. If the champion is in a semifinal, second-place team. Probably not necessarily the ACCCG loser. What if the ACC champ is in a semifinal that happens to be played in the Orange Bowl? It's probably unlucky for the ACC, but if they're smart they'll work it in where they get to place a second team anyway. If the Orange hosts a semifinal and the ACC champion isn't involved, then almost certainly the Peach Bowl, but it'll be up to the selection committee.
-- Big Ten: Champion to the Rose Bowl. Second-place team if the champion is in a semifinal. Possibility of placing a team in the Orange Bowl, if they have the highest ranked team among the eligible pool of them. If the Rose Bowl hosts a semi, and the Big Ten champ isn't involved, the Big Ten champ won't be considered part of the eligible Orange Bowl pool, and will go somewhere else, probably the Peach or Cotton.
-- SEC: Champion to the Sugar Bowl. Same arrangement as the B1G, just replace Rose with Sugar.
-- Big 12: Champion to the Sugar Bowl. No Orange access the way the B1G and SEC have. Champion will almost definitely play in the Cotton if the Sugar hosts a semi.
-- Pac-12: Champion to the Rose Bowl. Similar to the Big 12 and ACC, no second-bowl access. Probably send their champ to the Fiesta when the Rose hosts a semi.
-- Little Five: Highest-ranked of their champions gets to play at the grown-ups table.
To illustrate this, let's see what happens this season (assuming no more surprises the last two weeks) and no changes in the BCS rankings. We'll put the semifinals in the Sugar Bowl and the Fiesta Bowl, and I'll be a selection committee of one.
Sugar Bowl (semifinal): Kansas State vs. Alabama - funny, that would be the projected matchup anyway.
Fiesta Bowl (semifinal): Oregon vs. Notre Dame
Orange Bowl: Florida State vs Georgia - UGA is the highest-ranked team out of the B1G, SEC, or ND, and ND is in a semifinal.
Rose Bowl: Nebraska vs. Stanford - we are assuming the Rose has the same provision as the Sugar and Orange about taking the next-best team from a conference. It's a safe bet when the Rose Bowl is involved.
Peach Bowl: Louisville vs. Florida - Louisville is the highest-rated Little Fiver.
Cotton Bowl: Oklahoma vs. Texas A&M - there's no rule limiting the number of teams a conference can send to the new BCS, but I suspect they will have one prohibiting two conference-mates from playing each other. Clemson would be a strong Oklahoma-replacing probability.
There you have it. What else will change? Probably not much. It's all over but the details and the revenue-sharing. Of course, the revenue sharing is going to be the 10% that takes 90% of the time, but that's not my problem.
**Assuming the Big East stays that way. Boise State and San Diego State went east in a desperate fling for BCS access, which ain't happening. Don't be surprised one tiny bit to see that arrangement fall apart.