As the one who actually started the original discussion (at TWoP*) of what became the format of TAR 11 (All Stars, Returen of the Racers, whatever), I'm fully aware of the casting issues that arose from the approach TPTB took for the original "all-star" edition. I'm one of those who think the formula they use was not the best way they could have gone, in particular (in principle as opposed to the actual result) the creation of a team that had not competed that way originally.
The strength of TAR 11 was the route, and the fact that many teams were of about equal skill in that season. But as the numbers bore out, many of those teams (except for the frankenstein team) competed about as well in TAR 11 as they had originally (Oswald and Danny, for one example). My problem with casting that season is that they picked the teams TPTB thought were entertaining and enjoyable, or which CBS tried to ram down our collective throats as such, and frankly, TPTB's perceptions on that were off.
They need to resist the Russell Wentz (Survivor) temptation (bringing some back because they think that would make great television) and creating artificial teams. It is the casting methodology that was flawed the first time around, and I fear what we'll be faced with if the same approach is used again. Had TAR 11 been the "best of the best" as many of us had hoped, TAR 11 would have been far more interesting and would have generated far more interest than what we got. Can we hope that we can, at least have a higher presence of the "best of the best" and less of the artiticality of the alleged entertainment value of certain teams?
[*- I've never really explained how that came to be publicly, but that original discussion was started by me the the request of former Racers who wanted another chance to run the Race for the experience, and against the best competition. I had to get permission from TWoP's powers that be at the time, but their concerns were addressed and well, the rest played itself out over several years until TAR 11 began airing. I will say that I think waiting until after 9 regular seasons had been in the can to try it the first time was too long, as several seasons ended up having no representation. At least if georgiapeach's informed speculation is on the mark, TPTB will be working with six seasons and giving themselves a way to have two teams from each of the six seasons that would be included.]