I will get right to the points that teamfight tactics is missing.
* matches are not recorded in the match history!
* there is not a replay function for the game mode!
* while the items that the game mode has are good, it will need more than those!
* less than half champion pool.
* no honor system included.
* the game mode doesn't offer experience!
* loot system is not activated!
* there are no missions for the game mode!
A suggestion for the game mode when the ranked system will launch, it should have milestones like solo/duo. When you reach a certain milestone you can get a free a little legend and/or arena skin!