I've responded to Rob in my last post even before he posted, so I'm not going to repeat what I said there.
As to casting teams for jobs, they've been doing that since season one; in fact season one had two teams identified by jobs, just like this season (lawyers, teachers in season one; cowboys and detectives this season)...and the NFL wives in season four, identical twin models in season three, deli owners in season five, models in season 6, beauty queens in seasons 10 and 11, and so on and so on and so on.
There's nothing new about that aspect of it, and it's not new that Lynn Spellman marches to her own drummer at times with casting. There's no way to know who is going to survive each leg, much less all of them to the final three, and I can only think of two teams that made it to the finish mat that never, ever should have been there and got there by luck more than pluck.
I think this idea about the leg being unfair because of the one task being something that the cowboys is a false one, just as the fact that Joe and Bill lived in Paris for two years was unfair to the other teams in Paris in season one, or Frank and Margarita had an advantage on the final leg in TAR Classic in Brooklyn and we all know how that worked out.
The hypothesis is faulty to begin with, not to mention the conclusion drawn from it.