Gyarados
How is everyone so sure hydropump on gyarados is going to be legacy?
Answers
Nobody is sure. It's almost impossible to predict moveset reshuffle but giving Gyarados his best charge move with STAB for now, at least means potentially if it does get a water fast move (like Waterfall), it could be the top water type attacker.
This is just IN CASE Hydro Pump becomes legacy. If it doesn't that's great you can always get Hydro Pump. If it does though, even with TM you won't be able to bring Hydro Pump back, so it's a good strategy to have a decent Gyarados with HP for now.
No one knows. People seem to think Gyarados will get waterfall as a fast move. I would bet if it gets waterfall it will maybe be a 2 bar charge move.
I don't really think they will give it a fast water move. They can try to balance the game by not giving certain pokemon stab moves. Double stab moves on Gyarados would possibly be over powered.
https://www.reddit.com/r/TheSilphRoad/comments/7a92jh/the_silph_roads_apk_teardown_of_v0811_is_complete/
Waterfall was added to the move list as a fast move. That is where all the speculation is starting from.
The speculation with Hydro Pump possibly becoming legacy is for game balance. Give Gyarados a water fast move, but replace Hydro Pump with Aqua Tail. If that happens, I would also expect either Crunch or Outrage to be replaced with another 1-bar charge move.
To cover these possibilities for future legacy and TM use, I have at least one of each:
X/Hydro Pump
Bite/Crunch
Dragon Tail/Outrage