I created an account just to make this point.
While it is about time you offer a pack to unlock all characters, how about giving that pack to anyone who has already spent a certain threshold of money in the game?
I have spent over $100 in the game and do not have all the characters and only 1 cobalt due to crap RNG. This feels like a slap in the face that all of the sudden now you offer a system that I could have spent half that in. Unlocking characters with in game currency is basically impossible unless you only play this game and play it A LOT!!!