I would like to see an un-timed aspect of the game. After the introduce a new event or character, then perhaps in a month or so, they can reintroduce the event where you can complete the same challenges to earn the character, but don't have a time limit. People can work towards earning the character without all the stress. People who really want the character when it first comes out will play hard, or make purchases. For the un-timed portion, you can still keep purchase options.