Charla and Mirna VERSUES everyone!
I'm not a fan of three-peater teams but if I had to choose one I'd choose Charla and Mirna for the shenanigans.
"LEVEL FIVE CHARLA LEVEL FIIIIIIIVEEEE"
NO The new fans don't know who they are! So they are not eligible to run the race again 
I feel like the whole idea that new fans don't know who they are is kind of a weak argument on why teams early on should not return. I feel like the Amazing Race fan base has a lot of loyal fans who would love to see old racers. Especially with ratings dropping in recent seasons, the gimmicks that the race puts on might actually be turning away old and new fans alike. By bringing in old racers, it might bring back old viewers.
New fans "Not knowing who they are" being unacceptable says that "you need to know these teams in order to watch and understand this season". It's a ridiculous excuse when you look at the mess that was season 24, particularly the editing and realise you didn't need to know any of the teams to "get" that season.
Three-peaters-The Cowboys: Their storyline this season is "We didn't win and also we are cowboys". If you are a fan who followed the drama off the race then their storyline was "We were beaten by a sneaky gay guy in season 16 and a sneaky lesbian in season 18, I mean actually we got beat fair and square, but CBS won't air our opinion on LGBT people but anyways we need to win this time". But on the actual show we learn nothing new about them.
-The Globetrotters: Did they have a storyline in any of the 3 seasons? Big Easy is bad at mental puzzles and sometimes we do some tricks with items and they play our theme song over the footage is the most we got out of them. I like them but they did not need to come back.
-Margie and Luke: Out of the 3 returning three-peaters, Margie and Luke are the only ones who's storyline progresses from the past 2 seasons in that they cover Luke's sexuality in a throwaway 30 second clip. It's the only new thing we learn about them because other than that it's "Margie can run fast for an 'older' lady and Luke still has tantrums during tasks" which you can learn just by watching this season anyways.
The other teams-Natalie and Nadiya: They didn't have a storyline this season. I think they tried to say "look, they are fighting which is definitely what took them out last time", but actually it was a poorly designed leg with a couple luck challenges and a linear roadblock so it wasn't that they fought, it was that the race was dull.
-Mark and Mallory: Well they weren't even a team before so you didn't need to know their history, it's covered in the first episode. "Bopper can't race so I must win for him" is it.
-Joey and Meghan: You need to know that they were on the race before. This time they are less happy because they realised leg 1 that this course sucks. You may want to compare how they were not humble to how thankful they were before but it's not a necessity. Actual storyline wise they could be newcomers.
-Jessica and John: You need to know that they got eliminated with an express pass in hand. OR you would need to know that, if they won the express pass this season. They did not so they could be newcomers.
-Leo and Jamal: You need to know that they lost. Yeah that's covered in ep 1. The other teams don't know that they were considered sneaky on their season so it's not like they need to act any differently this season???
-Brendon and Rachel: They act slightly better than the first time they were on though no prior knowledge is necessary still have the same moments as before.
-Caroline and Jennifer: They ALMOST have a storyline that links back to their season when Meghan spills the T in an interview during leg 2 but then Meghan gets eliminated the next leg and Caroline and Jennifer just kind of...exist. Somehow. To 2nd place. While singing their song about winning. Which they don't. If they were a brand new team it would have changed nothing.
-Dave and Connor: Of all the teams this season this is probably the only one you need to "know" BUT then again you don't as they spend 12 legs talking about everything that they already covered on their first season.
Dave walks: "Ohhh hope my achilles holds up

"
Dave sits: "Oh now I don't have to worry about my achilles

"
Connor does a roadblock: "Glad I'm doing this as if you don't know already, we got eliminated in our first season because of my dad's achilles".
Dave gets U-Turned: "BUT ACHILLES, CANCER, I'M OLD, HOW DARE."
So their entire characterisation is pretty much covered again (to the point no other team has any story).
Sorry about the rant, but to sum up, you could bring back ANY TEAM from any of the previous 28 seasons and the "new fans" would survive because most of the teams are given a shallow 2 dimensional edit anyways. And with that I start my official petition to bring back Matt and Ana from season 1.
Please sign.