Magic Damage Immunity
If you played Teamfight Tactics from Season 1, you would know the Dragon trait with its powerful ability to grant immunity to magic damage. According to common logic, to possess such an overpowered effect, the Dragon trait would require extremely difficult activation conditions. However, just having 2 Dragon units (usually Aurelion Sol and Shyvana) on the board granted them that incredibly strong capability, completely countering magic damage-based compositions at that time.
Because of its great power and easy activation, the Dragon trait’s effect proved to be extremely unbalanced, even though Riot nerfed this effect later. Therefore, since Season 1 ended, Riot has never brought back the magic damage immunity effect to Teamfight Tactics, whether through traits or items. Even in the upcoming Season 6, Project Director Teamfight Tactics – Riot Mortdog shared on the stream of player Mismatched Socks that this mechanism will not appear.
Locking Opponent’s Items
Throughout all seasons of Teamfight Tactics, items have always been a crucial factor that greatly influences the meta game. In fact, the special mechanism of the current Season 5 revolves around Light and Shadow Items. Therefore, having one or more items locked would severely weaken the power of a team composition, potentially ruining the player’s efforts. This happened in Season 1 when Riot Games introduced the Technology trait that could lock opponent’s items for a few seconds.
The frustrating aspect of this mechanism is that it cannot be countered by unit placement or items… because the effect of the Technology trait always activates at the start of a round. Indeed, the match becomes very unfair when one side possesses a strong effect that is nearly impossible to counter. Perhaps due to the deep lesson learned from the Technology trait, the ability to lock opponent’s items will not have a chance to return in future seasons, including the upcoming Teamfight Tactics Season 6.
Reducing Enemy Champion Levels per Attack
Another mechanism that Riot Mortdog confirmed with player Missmatched Socks that will not return is the effect of the Curved Sword. The initial idea of Riot was to create an item that could counter hyper-roll compositions and push champions to 3 stars too quickly. However, the downside of this mechanism is that it activates randomly on hit. Thus, this item was only suitable for the Marksman trait in Season 1 to snowball the game and was rarely used as originally intended.
This led to a consequence where Marksman compositions with low-cost champions like Tristana and Graves could defeat stronger opponents if the player had “good luck”. Clearly, this is a very unreasonable situation, so Riot Games removed this item immediately after Season 1 ended and has never brought back the effect of reducing enemy champion levels per attack again.