I would not be surprised if Sheilla retires after the OG not only from the NT team, but from volleyball in general, or at least take a break to have a child.
I would not be worried about Brazil, after 2004 and with that dramatic loss for Russia, lot of the Brazil`s legends retired from the NT like Virna, Erika,Elisangela,Venturini,Arlene, Fofoao( she came back later)..and nobody knew what was gonna happen with the Brazilian team...but then Brazil built their best generation ever and started by taking the Grand Champions Cup 2005 over the Olympic Champions China...
The difference is that in the Brazilian SuperLiga all the young new talent are actually playing the game....while in Turkey,Italy and some others the young talents are sitting on the bench and not playing the game....
I wouldn't be worried about Brazil but they will definitely lose more when this generation leaves than they did in 2004. This generation is much better than Erika, Elisangela, Leila, etc. There will always be talent in Brazil because of the importance of the sport in the country and the structure the game has but with the exception of Gabi, there are relatively few younger players that are either extremely physical or extremely skilled which allow them to play at the highest level. I anticipate they'll go from top 3 in the world to top 5, which is not a huge difference but a difference nonetheless. Natalia, Gabi, Dani Lins, Fernand Garay and Tandara (who still needs to demonstrate she can get back to her prior form) will all be around and is a good base to start.
The Rio 2016 roster looks exactly like I anticipate. While Ze certainly wanted to get Roberta the reps she needs to be able to play in the next cycle, the experience level of Fabiola vs. Roberta is undeniable. Tandara wasn't nearly in good enough shape to make the Olympics and before the medal rounds, I think we'll see Natalia play OPP against some of the weaker teams. While they won't get much time, Adenizia and Juciely have been with the program for sometime and are great players in their own right. The most unfortunate cut was Camila Brait but Leia was playing out of her mind during the WGP and it was a touch choice.
While I am rooting for the USA to take the gold, I live in Brazil and it would be an amazing feat if Brazil were able to take home the gold in Rio. If the USA can't take it, I hope Brazil does.