Remember: rumors are NOT meant to be taken as confirmed information, simply as a starting place for discussions. This rumor in particular is highly suspect and serves as an interesting idea, but please do not place any faith in it.
An anonymous 4chan poster had this to say about the upcoming games:
Cover art features the wolf legendary in each of its 2 formes depending on the version. In the background a larger Pokemon’s shadow looms over it: a winged beast shape in Sword (a dragon?), a humanoid shape with one eye in Shield (a cyclops?).
New battle mechanic based on distance. Sky battles return. Marine battles for Pokemon that can breathe under water. Diving returns but under water battles/encounters require marine Pokemon.
Galar is known for many of its native Pokemon having branch evolutions. Around 40 Galar species evolve differently depending on what version you own. New branch evolutions for older Pokemon including Johto starters, one of which you receive from Elm, who has come to study Galar’s mysterious effect on evolution.
This new feature encourages trading but you can also obtain the alternate evolution in a postgame safari area located on island to the right of Galar accessible via ferry from Water gym city. The island also has the and battle frontier.
Strong Pokemon trainers in Galar are invited to join official league teams and compete in team battles at gym stadiums. The two highest ranked teams are Team Sword and Team Shield. The top ranked team will ask your rival to join them and the second ranked team (Sword in Sword and Shield in Shield) will ask you to join them. You eventually agree as a favour to the Galar Champion so that you can investigate the top ranked team.
Technically there is no “evil team” in the game but the top ranked team are arrogant and are your main opponents. They have an evil captain and a manager with much more sinister plans that require his team to stay on top to make money from sponsorships. The top ranked team is based in the modern city in the north while your team are from the industrial city in the south. The team captains each possess the wolf legendary in its respective Sword/Shield forme. Once you prove yourself in battle, your captain entrusts his to you to stop managers secret plan.
It would certainly be fun to explore a region known for branching evolutionary paths. No region has truly focused on that aspect and with the way that the regional Professor’s research has impacted the game (Mega Evolution in XY, Z-Moves in SM) it does seem somewhat plausible.
Getting rid of the “traditional” evil team sounds like another trope Game Freak may be willing to toss aside for a slightly more new take on challenges within the game from other trainers.
My interest is definitely piqued! Give your take in the comments or head over to our Rumors channel in Discord and chat away!