Riot, for the next preseason, you should update the game a little at a time.

Why ? Simply because pushing a lot of change at the same time is hard to balance. Also, when something become "OP" due to a pre season change (Exemple : Yasuo or trynda) you can ban those. Currently, there is so much thing to bans that bans are useless anyway.

You could have done something like :

Week 1: New masteries, rift Herald. Generals balances changes (TP nerf , ...) Week 2: ADC reworks. + AD items reworks Week 3 : Other items changes (Hi guinzo-gunblades.) Week 4 : Winnions, turrets changes.

Every week, riot balance the majors issues. It's not a big problem if some smalls balances issues or , if it isn't perfect, those can be fixed later, but it would help to keep the game relatively balanced during the transition. Idealy, that should be done on the PBE, but everybody knows that the PBE isn't for balance changes, since the player base is to small for that.