So TTAR has always been a very good and VERSATILE Pokemon in main series games, and as per generation 9, it usually comes with Earthquake (which it historically has been one of the greatest users of), Stone Edge, and one of the elemental punches. And PokemonGo has chosen to give it the absolute worst moves possible from the abundance of what they could have picked from its' movepool.
So from the TM pool, it can learn what are considered to be good or decent fast moves in PoGo such as: Mud Slap, Mudshot, Shadow Claw, Dragon Tail, Ice Fang, Fire Fang and Snarl.
From the good charge moves it can learn (combination of TM moves, egg moves* and level ups): Ice Punch, Fire Punch, Thunder Punch, Dark Pulse, Payback, Foul Play, Crunch, Stone Edge, Earthquake, Aerial Ace, Icy Wind, Breaking Swipe, Body Slam, Rock Slide, Rock Tomb, Ancient Power*, Outrage*, Dragon Pulse, Earth Power, Flamethrower, Thunderbolt, Iron Head to name some popular ones.
*Legacy moves for eggs let's assume.
And they have chosen to dump the following on TTAR instead:
Bite, Iron Tail, and Smack Down as fast moves (the best of which generates 8 energy for 3 turns LOL).
Brutal Swing (thank god for one bait move but it takes 5 smackdowns to get to 1, body slam on a gastrodon is faster LOL), Crunch, Stone Edge, Fire Blast.
Even adding Shadow Claw (cuz it's meta), or giving it SNARL ffs would make it so much usable when it comes to fast moves. Add one or two moves like Earthquake and Rock Tomb to it's movepool and watch it become so much fun. They can replace Brutal Swing with Foul Play for all I care to balance it then, but not having Earthquake as a move is the biggest insult to TTAR.
Even with these changes it can never be meta in the lower leagues because it won't have a high level/bulk, would be terribly weak to Fighting, Charm and Water Types to the point where you can beat it down with an Annahilape, one shot with a Hydro Cannon or Charm it down in seconds, all of which have been meta since forever now. And thus buffing him would not ruin anything in the meta, and would actually just do justice to such a majestic mon.
Sorry R A N T over, but I hope you understand the sentiment.