Niantic has announced that there will be some upcoming changes to Pokémon GO to balance the gameplay a bit more. The changes will come into effect throughout October 2019.

Community Note: Combat-system updates, more attacks, and other changes coming to Trainer Battles

Trainers, In our previous Community Note, we outlined some changes that came to Pokémon GO that made Trainer Battles a more fun and competitive experience. In this update, we’re excited to announce more changes focusing on Trainer Battles! Over the next couple of weeks, you’ll see some changes in Pokémon GO’s various combat systems.

Updates to the combat system
Our team has polished the existing system to make Trainer Battles and Team GO Rocket battles more intuitive and responsive in Pokémon GO version 0.157.0.

• The timing for damage dealt and energy charged has been improved.
  • We understand this issue provided a possible knowledge gap that players could learn to work around, giving them an edge in battle. We chose to adjust this since we think it was fundamentally unintuitive that damage and energy changes always ran one move late. Unlike with quickly switching before a predicted Charged Attack, we don’t think the particularities of our refresh rate make for interesting gameplay decisions.
• A Pokémon’s health bar will briefly pulse when it receives damage.

Exciting updates to existing attacks in Pokémon GO!
Along with updates to the combat system, there will also be some updates to select attacks.

• Bubble Beam - Bubble Beam will now have a reliable attack debuff, which decreases an opponent Pokémon’s attack stat by one stage. We’re excited to see what strategies this change kicks off.
• Power-Up Punch - Power-Up Punch’s primary purpose was intended to be rapidly boosting the attack of your Pokémon if your opponent doesn’t respond quickly. The damage for Power-Up Punch will be decreased in order to help Pokémon that can learn Power-Up Punch play differently from one another by using their other attacks for damage. This should also provide clearer counterplay—not blocking your opponent’s Power-Up Punches is now a more obviously right response!
• Psychic - Psychic will now deal more damage and be usable sooner in Gym, Raid, and Trainer Battles. This rework is intended to make Psychic a more viable Psychic-type attack in both raids and Trainer Battles. Trainers now also have the chance to decrease an opponent Pokémon’s defense stat whenever the move is used in Trainer Battles.
• Snarl - Snarl has been updated to have a clearer energy-generation role among Dark-type Fast Attacks. This should help the primarily offensive-leaning Pokémon with Snarl, like Arcanine and Luxio, use important Charged Attacks before fainting, as well as giving the more defensive Suicune and Umbreon more frequent access to their Charged Attacks.

More attacks will also be coming to Pokémon GO!
Certain Pokémon will soon be able to learn attacks that hadn’t yet been seen in Pokémon GO!

• Thunder Fang: An Electric-type Fast Attack - Arcanine, Steelix, Mightyena, Hippowdon
• Ice Fang: An Ice-type Fast Attack - Suicune, Mightyena, Mawile, Hippowdon, Drapion

Fire Fang damage has been increased to match the damage that Thunder Fang and Ice Fang deal.

Additional moveset updates
The following Pokémon will be able to learn attacks they couldn’t before:

• 026 Alolan Raichu: Thundershock - This Fast Attack will let Alolan Raichu surf its way to faster Charged Attacks to help make up for its light defenses.
• 028 Alolan Sandslash: Ice Punch - This Charged Attack lets Alolan Sandslash more reliably dish out fast and high-powered Ice-type damage in the Great and Ultra Leagues.
• 038 Alolan Ninetales: Charm - This addition allows Alolan Ninetales to have a powerful Fast Attack option as an alternative to its more Charged-Attack-focused Ice-type attack set in the Great and Ultra Leagues.
• 055 Golduck: Bubble Beam, Synchronoise, Cross Chop - With access to a few new tricks, Golduck has a new and unique pool of Charged Attacks that should help it stand out against the many other Water types in Ultra League.
• 105 Alolan Marowak: Fire Spin, Flame Wheel - Alolan Marowak’s original move pool made it hard to use any Fire-type attacks in practice. Adding Fire Spin and Flame Wheel should give this Pokémon options to reliably deal Fire-type damage.
• 226 Mantine: Bubble Beam - Giving Mantine the new and improved Bubble Beam gives it a more supportive role among Great League Water types.
• 303 Mawile: Fire Fang, Ice Fang, Power-Up Punch - Fire Fang or Ice Fang combined with Power-Up Punch allow Mawile to pose a real threat in Great League. Mawile’s weakness to Fire-type attacks keeps it a balanced competitor.
• 461 Weavile: Snarl - Snarl allows Weavile to hold its own as a fragile but powerful Dark-type attacker against Team GO Rocket, Raid Bosses, and Master League opponents.

We’re excited to see the teams you build with these changes, Trainers. Stay tuned, as we’ll be sharing more updates like these in the future. Good luck on the battlefield!

Source: https://pokemongolive.com/post/trainerbattle-rebalance-september2019