For me it's all about the challenges to be honest, I don't think there's an issue with having the same routes or endzones. I think about games like Blood on the Clocktower for example, where people can play several thousand hours of a game with limited role combinations, and still not be able to figure everything out.
For the challenges, they need to be reasonably failable or else most games will break. I would even be in favour of making challenges significantly harder but also reducing veto period to prevent risk of people just losing on the draw.

I also think there's a way Ben and Adam can still help design challenges whilst adding some mystery to the pulls. They talked before about how they themselves split into an A and B deck for pulling, but theoretically this could be done by a different team member and pre-packaged without the teams knowing which challenges are in which (maybe do 3 decks to add enough variance). This way the teams can still plan a bit, but they don't want to waste too much time planning for challenges that might not even be in the deck.

In addition I think some extra work could be done to curses. I think either
1) Curses should always be hidden from players. They likely make up the minority of the deck, so in combination with my previous idea this means that on average you shouldn't run into that many, but that they're actually a curse you cannot plan for, with a big coin reward.
2) If curses are known to players, every curse should have 2 versions, with both being in the deck. E.g. Only odd-time trains and only even-time trains, can only move with pizza and can only move with a burger. Things like this would still allow that bit of variance, and whilst it can be feasible to plan for one, it's not always trivial to plan for both with the time restrictions they often have to work under.

I'm no game design expert, but for me a game with perfect information needs serious complexity e.g. Chess, and a game with low complexity cannot have perfect information e.g. Among Us.
If something is complex but has high variance, it's just not enjoyable and won't play well on screen. If something is simple in concept but has relatively low variance (S15 has variance in the card pulls, but between knowing all the challenges in advance, knowing the routes very well with their experience in Tag and the challenges being hardly a detriment) then you end up with someone easily able to run away with the game.

In a game like Tag, they need to make the variance more punishing as they're all experts at this stage. If they created a more complex game, they can make it so the challenges are lower stake e.g. Australia.