new mastery system is just a step backwards

current masteries are really atrocious. Riot took away the most important thing i liked in them - freedom of choice. i could take anything i wanted, even 0/30/0 if i wanted full tank, now i'm forced to take masteries which are completely useless for my class. and if we are talking about tanks, let's be honest, these defensive masteries are horrible, except the keystone which really doesn't matter, it's one mastery after all. the difference in taking defensive masteries and not taking them, is 1 auto from adc. and let me add, previous masteries would be much better at dealing with all these incoming crits in preseason, would actually separate a tank from a squishy (especially that tanks have enough problems on their own), and VERY probably would be healthy in balance terms (but it's preseason, so who cares about balance) but the saddest thing is, there is absolutely no diversity. for example, there is dedicated tank player who wants to go full defence. he HAS to go (let's say) 12/0/18, while any ad champ will usually go 18/0/12. now i'm sorry to bother you, but what's the difference? 300 hp and 15% tenacity? that should be the difference between 2 completely different classes, damage dealer (who ignores defence) and a full tank? sorry, but for me it does not have any sense at all, and instead of improving masteries, you destroyed them and made both diversity and balance worse