I’ve not tried this myself but it seems TW is giving good experience according to Reddit
Time walking dungeons are giving like 450k+ exp per dungeon at 50+, if you’re levelign an alt here’s a heads up. I just went from 55 to 60 in 3 dungeons.
https://www.reddit.com/r/wow/comments/oxj9ao/time_walking_dungeons_are_giving_like_450k_exp/
Edit - to stop the reddit link from stretching the forum column width
Is it a bug or what ? last time i’ve played TW reward was 5k xp
Peering into my crystal ball I see this being “fixed” followed by pages of salty “fun detected, fun removed” memes.
Place your bets!
it’s 100% going back to 5k exp tomo lol.
I cant grasp the amplitude of their desicion making, they nerfed old TW xp gain aka 3 dungeons to level up, only to give this much xp in 9.1
And ye last TW week it was the same i believe…
Either way it feels like exploit to me, so i dont plan to abuse it until they confirm its intended.
Got 4,5 levels from 3 TW dungeons, beats spamming those 4 SL dungeons 
just went from level 56 with ~10% to level 57 with 43% from one dungeon. this feels really, really good, i pray they dont revert it to 5k per dungeon. 
That’s how I lvled my alliance chars on the previous timewalking event. It was way faster than spamming SL dungeons.
edit: It didn’t give as much exp as this seems to do, didn’t see the exp gain on the screenshot at first, lol.
Nerfed already
Got 50k.
Seems fun was detected:-
Classic blizzard… so many issues but when a positive uninteded side effect happens that DOESN’T affect power they just gotta nerf it into the ground.
knew it… i just knew it…
cant believe this actually makes me sad. i was about to level some characters to level 60 this weekend but yeah…not going to happen…other games it is then…
What is Blizzard doing?
Why they’re so focused on ruining people’s experience playing the game?
It almost feels like they’re intentionally truing to upset it’s costumers…
Levelled 4 characters during last WoD timewalking week, wanted to do the same this time, rip
And they fixed it, so sa story. It was so good experience to leveling. But now we left only with pain. This expansion is nightmare.
Did some Time Walking earlier today with my main, for the weekly quest, and saw people powerlevel throughout that. Thought that it’d be fun, so I ran a few dungeons this night and… well, it’s been nerfed into the ground.
I thought I’d have a reason to renew my subscription. Guess not. 
Was planning on logging in to actually level some characters but back to other games it is I guess
Fun detected, fun detected.
Sigh Blizzard, you are absolutely terrible at this sort of thing, make a game dedicated to getting to the end game, make it a chore to get to the end game.
Got quite excited for leveling some alts for once but nah, will hop back into FF14 for the day and ya know, quickly level a new job.
I swear this company loses every ounce of the understanding in the word fun, proper annoying this sort of thing when you think they’ve actually done something cool and… nope, system error, game not being played at designed, error error error, fix it quickly the treadmill has changed speed.
Ugh.
The ball did not lie.