Personally, I would love to see a fan cast returnee season, even under the same rules that Survivor is using. My only concern with how Survivor is doing it, and how it would be done for TAR is that the casting would be from the teams chosen by the usual suspects. As was the long running argument prior to the original All-Stars season, how TPTB would select and how many of the fans would select were and are not the same.
Therein lies the problem.
What might work is a preliminary online voting round where all the teams who had not won nor returned for additional season(s) would be listed and possibly go to as many rounds as needed to get the total down to a reasonable number for a final vote. If a team couldn't or wouldn't do it as their original team, then that could be vetted during the process. That's the step Survivor didn't follow, and it is what weakens the approach they are taking.
The other thing to keep in mind is that there have now been well over 200 teams, 500 Racers (don't forget there were 40 Racers on the Family Edition of 10 teams and something would have to be worked out for those folks) but if done through a series of rounds, it could work. And I think it would get a lot of attention.
The one unfortunate thing is that because of the two earthquakes and heavens knows what else with Nepal, it may be years before we can hope TAR finally gets there. (Before the earthquakes, in response to a live chat question, Phil had said they were in fact working on Nepal.) I still want them to go to Antarctica; it'd primarily a question of filming during the summer tourist season where there are ways to travel from South America. If only they had done so during TAR 11.....