I need to qualify my response because it is based on my observation and feel of the game rather than a statistical analysis so take for what it's worth.
The impending doom of the 1 RB system and it's impact on fantasy football has been predicted since I've been playing this game (1999). It hasn't happened yet and I'm not sure it will in the sense that it changes how we draft and build our teams.
First, let's consider where we are with the teams in the conference finals. Let's look at them 1 by 1.
Chicago- They have been waiting to put Benson in as the feature back since he was drafted. The only reason they haven't yet done so is because of Benson. While Jones has done a great job IMO-they just don't want him. They wanted Benson to be the guy but Benson has not endeared himself to the team as the guy they can count on. That may yet change so stay tuned. This RBBC is not by design and likely won't stay that way if Benson gets his act together.
New England-Maroney is being fazed in and Dillon fdazed out. Dillon is no longer a realiable feature back. His days are numbered. But he still adds value and experience and that make the rookie's adjustment easier. It makes sense the way they handled this. I fully expect Maroney to be the guy in the nest year or two. Of course they will always have a 3rd down back role player and Faulk is the best at that.
Saints-This may be the one that makes the most sense. McAllister was coming off injury so there had to be some concerns about how well he'd recover. But remember, Bush was never expected to be there. They were handed a gift from Houston. How could they pass on Bush? Now they have truley a 2 back system that they effectively utilize with great success. What other team has 2 backs of their caliber? I think they are simple taking advantage of what was given to them.
Colts-I said all along that Addai was drafted to be the man and it appears to be headed that way. He's the one they've been leaning on the most down the stretch. Rhodes os better suited as a back up and it's paying off for them. Expect more of Addai going forward and Rhodes as a change of pace player.
Now, with that said I think the whole RBBC idea is more media driven then reality. Outside of the Saints, what team really used the RBBC except for teams in transition? NE, Indy and Chicago are teams in transition with their RB's. Outside of a change of pace role back, I doubt Jones, Dillon or Rhodes will have much value going forward. Maybe Jones becasue of Benson's questioable acts but even that could change next year.
The Saints are the 1 team I see that will likely continue doing what they're doing going forward. Keep something in mind. Good RB's need reps to get into a good rhythem. 50-50 touches do not work that well for many reasons. Not all of them are good pass blockers and that leads to continuity for QB's and the passing game. Not all guys are versatile enought to command a lead role. The better talent will always be on the filed more than the other guy. The Saints are the exception.
Lastly, teams have this thing called salary cap and they can't afford 2 ball carriers that are starter material and the salary they command. Having 2 of them means the team suffers elsewhere. They just can't do that ongoing. Coaches realize that these 4 teams are not in the SB because of the 2 back system. It's a team game. It's not just the RB's or the QB's as many tend to think. It's the body of the team does. That's why the cap has to be managed judiciously. Failure to do so means no playoffs chances for thie teams.
Lastly, absent of starter requirement changes in your leagues, you still need good RB's in order to win championships. In fact if the RBBC really comes through for say half the teams then expect your top level RB's to become even more valuable, not less.