A breakdown of the upcoming changes to Raid Battles and movepools.
In short, Raid Bosses will have a buff in HP during the battle, making them harder to take down. This means that Palkia is no longer duo-able with optimal counters, friendships and weather. This could also mean that Deoxys-Attack is no longer solo-able. Please plan accordingly.
Mainly, what will be changing is move power for some of the moves. Some will be adjusted only slightly, but Shadow Claw will be a boost, which is a boon to those Legacy Move Gengar.
Ice Beam has been boosted in raw power from 65 to 90, which makes it stronger than Blizzard and on par with Avalanche. It also states that Flamethrower and Thunderbolt will be rebalanced for standardization purposes. That means Flamethrower will be boosted from 70 to 90, and Thunderbolt will be boosted from 80 to 90, if what they mean is accurate.
Also, the movepools for many Pokemon have been changed. Many of them seem quite off the cuff, but I found some useful ones:
Kabutops can learn Waterfall, finally giving it a pure Water-type moveset
Aerodactyl will be learning Rock Slide, making it even better.
Donphan can learn Mud-Slap, giving it a pure Ground-type moveset
Ho-Oh can potentially learn Hidden Power, which means if you’re lucky, you can get either a Fire or Flying Hidden Power, which would finally give it a pure moveset. Sadly, it could also mean that you could get a more rotten move
Roserade will be learning Grass Knot, which will capitalize its speed to help attack more often than Solar Beam can grant
Honchkrow will learn Sky Attack, which will give it a major boost as a Flying-type attacker
It seems the majority listed are to act as Dragon-type counters. It’s possible due to Gen 5 being so Dragon-type heavy that they decided to do this to prepare, also to help against Palkia.