Give Gyarados Crunch

[TheTainted_Wisdom]

I mean, it wouldn't. Impossible to get a canon level-up move? Sure, fine; maybe they just didn't keep up with all the updates. But if they were to implement Gyarados having the move but make it tutor-only, it'd be a disgustingly painful kick in the pants to not be able to get one of its staples until 7 gyms in, and this is not an easy game, so without Crunch, Gyarados falls off pretty soonish considering the only good Water-type move it has access to is Waterfall; Dive is an effective BP of 40 because it takes two turns, and the other moves run off of its  Special Attack.

It learns Aqua Tail on its own, it's got access to Thrash if you use the move reminder, Dragon Dance boosts its attack power even further along with speed, and it would get access to Crunch just before it gains access to Mega Evolution and would actually be able to take advantage of STAB damage from the attack.

"and this is not an easy game"

...Really? Once you get access to an Eevee after getting a Nuclear type in your party so that it evolves into Nucleon, pretty much everything in the game might as well pre-emptively bend over and ask for it gentle because they are F*CKED.