I was bored and compiled most of everything said in this thread. So here you go:
TASKS & ROUTE MARKERS
- a good, difficult, confusing finale memory challenge
- increase number of U-Turns, and/or bring back Yield, Intersection, Hazard, and single U-Turns
- a difficult starting line task
- increase the number of night legs
- increase self-navigation and self-driving
- bring back the departure time slots for the next day of the earlier seasons
- odd eliminations (e.g. at Keep Racing legs, double-elimination at Leg 11)
- remove Keep Racing legs if it's not going to be a double-length leg with a bunching transportation in between.
- choose another starting line city
- visit new countries and one-time visited countries more
- no linear tasks, get tasks that are confusing and would take timeand change placements (and not 5-minute tasks where teams finish in the order they went in. IIRC, they used to cut those out of the episode, and now...)
- increase difficulty of all tasks, especially Fast Forwards
- present Fast Forward as a strategic option rather than an auto-first place button. And never just have ONE Fast Forward per season (e.g. 4 to 6)
- try a season of not visiting Asia
- allow teams the more freedom of choice for transportation
EDITING
- more than one-hour premieres (1.5 or 2 hours long) that features only the first leg, making it a difficult one.
- return the suspenseful and grandeur feeling of the music of the pre-S18 seasons.
- DO NOT encourage team theme songs
- add effects akin to TAR Canada and TAR Australia
- don't skip any teams' arrival and finishes in tasks and clue boxes, I mean c'mon.
- don't cut the intro's team montage
- equal airtime for teams
OTHERS
- the location signpost at each pit stop.
- return of the Elimination Station.
- Behind the Scenes type of program for TAR
- make clues so teams actually have to decipher them.
- allow teams to find a Fern (a local tag-along helping a team)
- allow teams to interact with each other during downtime and show some of it
- add a fresh twist per season
- cut teams evenly (e.g. for production-provided flights) but never too far apart
CASTING
- change of mechanics of casting the teams
- increase everyday people teams and decrease used-to-camera teams or pro-athlete teams
- return of teams from the very early seasons for an All Star season (S1-S13, S19)
- increase number of all-female teams per season (constant number 4 MM teams, and a record 8 MF teams in S6)