I'd actually love to see a weekly set of parkour challenges with a varying layout for the week and prizes based on how quickly you can get through it. Think of Super Mario 64 with that one bowser level all the way up in the air (so they dont have to waste resources on background/design) mixed with some of the designs/ideas from the Vancleef hallucination fight and ToT Treasure Hall run. There would be 3 various difficulties with a random order of 5, 10 and 15 encounters that are taken from a pool of encounters.
One encounter would be similar to the Vancleef run where you go through that tunnel with rotating electrical orbs that would kill you, where the normal mode is a giant platform with them and the Expert challenge would have it as a number of blocks that you have to jump around while avoiding them.
Another would be a layout of those mogu runes where you have to figure out what the safe path is, while the next encounter could be a giant cube you jump into and have a puzzle room where you there are a bunch of clickable objects and you have to find the correct objects to click on to open a door and continue (3 wrong clicks and the bottom opens letting you fall to your death!!!). After each encounter there is a "spirit healer" zone where you run into a light circle to ressurect your character (so you don't have to be at the mercy of the 30s rez timer and have varying rez times based on if you died 3s before it reset)
There would be a set time challenge that gives you a prize for completing once a week (5 minutes=gold 7 min=silver 9 minutes=bronze), a small prize for each completion, and a leadership board on each difficulty for those with a competitive nature. If you win 1st place on a leadership board, you get an extra prize for that week.
EG: Each leadership board has a top 10 of the week. You play Easy and get 1st place, Normal and get 4th place, and Hard and get 2nd place.
1st place Easy gives you 1000 Azerite/gold and 10 tokens.
4th place Normal gives you 1100 Azerite/gold and 16 tokens
2nd place Hard gives you 3,000 Azerite/gold and 25 tokens.
You will get 5,100 Azerite + 5,100 gold for that week as well as all those tokens you can use to redeem at a vendor.