So many people want mythicals
So as of right now, the biggest means to get them are tokens to buy the gold package (has highest percentage chance to get a mythical). Silver package has small chance as well.
Otherwise, the only real way to get mythical's is to win the clan rankings.
So I will say, mythical's are essentially only for those who buy tokens, or have a great clan at the moment. This should be changed to be available to non-paying users, but still very difficult.
The idea presented could work if you only make the last 2 give a chance. And I would still put those chances at
50000- 1% chance
100000, 2% chance