The following team compositions seem extremely 'weak' after the implementation of Patch 12.13 in Clash Arena Tactics.
Nidalee - Shapeshifter
In the recent Patch 12.12, Nidalee - Shapeshifter was perhaps the only 'rush' composition remaining viable as compositions revolving around Ezreal, 3-star Sett had completely vanished. The reason being Riot increased the strength of the Dragon tribe, making the chance to acquire a 3-star Nidalee significantly higher. This allowed players focusing on Nidalee to possess immense power mid-game, reaching level 8 and achieving the 6 Shapeshifter strength threshold.

Perhaps Riot Games didn't want the 'rush' composition archetype to become too prevalent, so they continued to significantly reduce Nidalee's strength in Patch 12.13. Specifically, Nidalee's attack speed and spell damage in her transformed state have been reduced, weakening her damage potential considerably. Additionally, Riot further weakened Swain, a crucial champion in the Shapeshifter composition mid-game, resulting in a significant overall reduction in the strength of this playstyle.
Jade Dragon
SyFen's counterpart, Shi Oh Yu, is also an immensely powerful Dragon God champion, ensuring points for players. Unlike SyFen's randomness, Shi Oh Yu's method is much more reliable, so as long as players equip this champion with the proper 'dispelling' equipment, this little Dragon will 'carry the team'. Additionally, other pieces of Jade Dragon like Neeko, Gnar, or Anivia all bring certain versatility and help Shi Oh Yu deal significant damage.

However, this might not be so certain in Patch 12.13 as Riot decides to significantly reduce the strength of Shi Oh Yu's position. Firstly, there's a substantial reduction in damage when interacting with SMCK at the first two levels from Shi Oh Yu's abilities. Moreover, the time to stun opponents is also slightly reduced. These changes greatly diminish Shi Oh Yu's 'team-carrying' ability, making this champion no longer a powerhouse.
5 Gold 3-Star Composition
Recently, an extremely strong composition emerged in Teamfight Tactics, revolving around 5 gold 3-star champions. This composition operates by leveraging the Dragon God mechanism to fuse the insignias of this tribe onto a 5-cost champion and striving to upgrade them to 3 stars. This playstyle proves extremely powerful in a specific match because upgrading Dragon God champions has become much easier than before.

However, this playstyle will be completely eliminated in Patch 12.13 as the Project Director of Teamfight Tactics - Riot Mortdog announced that the Dragon God insignia will be removed. This is a sensible decision by Riot because the essence of the Dragon God tribe relies on its mechanism to upgrade itself to 3 stars. Exploiting the Dragon God insignia as mentioned above goes against this, and the fact that it's being removed is understandable.
