When a lot of people using same thing - it's concidered ovepowered. For example, if some champion or rune will have 80%+ pick rate - it most likely will be removed or reworked. But, somehow, this rule never touched flash - a summoner spell that good, that it has over 90% pick rate. Why? Isn't there suposed to be variety of choice, instead of "pick flash or be behind"?