Unbalanced classes

I had a lot of high hopes for this new set coming out on live. I thought the new classes, champs, and even the skins were a good idea, opening up new strategy's and just an overall new feel, however I'm sure that I'm not the first person to post about the imbalance of certain classes to others. mainly my issue is with predator. giving a unit the ability to execute at 25% health, along with steel and crystal making units nearly impossible to kill. a 1* kog can sit in the back line and kill multiple 3 star tanks because of a class that is way to strong and never be touched. I don't understand why this was released live. I could understand a 10% execute, but 25%. I mean literally 1/4 of a units health bar, this is overpowered. please give me some insight why this hasn't been addressed.