Lets see what Tanks lost in preaseason and why this season would be the end of tanks
Masteries
1-Enchanted Armor Increases bonus Armor and Magic Resistance by 2.5% Increases bonus Armor and Magic Resistance by 5% Increases bonus Armor and Magic Resistance by 7.5% Increases bonus Armor and Magic Resistance by 10% (Nerfed to 6%)
2-Reduces damage taken by 4% from Area of Effect magic damage (Removed without even adding something better)
3-Hardiness +2 Armor +3.5 Armor +5 Armor (Removed no more 5 armor....when all ADCs have better AD and doran blade is stronger...)
4- Legendary Guardian +3 Armor and 3 Magic Resistance for each nearby enemy champion (Nerfed to +2 plus the worst now it make you choose against the Tenacity mastery when riot already nerf the tenacity boots so you need the tenacity now more than ever if you are a tank so lets just say this mastery is removed)
5-Oppression Reduces damage taken by 2% from enemies that have impaired movement (slows, snares, taunts, stuns, etc.) (Added in to Offensive tree which mean tanks cant get it any more unless if they go glass cannon tanks because you know riot balance...)
6-Reinforced Armor Reduces damage taken by critical strikes by 10% (Removed and now the game is full with critical strike items....)
7-Resistance +2 Magic Resist +3.5 Magic Resistance +5 Magic Resistance (Removed...)
8-Second Wind Increases self-healing, Health Regen, Lifesteal, and Spellvamp by 10% when below 25% Health (Removed) Good bye mundo or WarWick/etc
9-Unyielding Melee - Reduces all incoming damage from champions by 2 Ranged - Reduces all incoming damage from champions by 1 (Removed and Riot didnt even bother buffing Doran shield....)
10- Veteran Scars +12 Health +24 Health +36 Health (Removed and i know they make the 6% new max hp mastery but this mean that this 2 masteries combine at live server provide you more hp than the new mastery till 1100 hp a tank have 1100 hp after he buy the mini sunfire so pretty much a huge nerf to early game tanks)
Items
All armor items got Nerfed (Their price got nerfed) and i know that riot add more Gold per 10 for everyone but 500 cost increase in some Armor item you would need 45 minutes with the new GPP10 to match the new price so yeah its str8 up nerf! Plus the new Giant slayer item that pretty much punish you for building HP but wait there is more this item now is builded from L.W that mean that one item now counter both of your armor and HP.
The only "buff" that i see for tanks is for the Frozen Fist that now provide 20% CDR that pretty much mean nothing because from all tanks only Malphite can make use of that item
So yeah if you dont play ADC or bruiser just go play fallout4 or something else because if you play any other role you would not be able to do anything