Any GOOD reason behind buffing Zed/Akali and nerfing mages like Brand/Lux/Ziggs?

Akali Base AD increased from 62.4 to 65 Base Armor increased from 23 to 28 Base HP increased from 550 to 630 AD per level increased from 3.3 to 4

Brand Base Armor lowered from 21.88 to 18 Armor per level lowered from 3.5 to 3

Galio !

Graves HP per level lowered from 92 to 85 Base Armor lowered from 33 to 30 Armor per level lowered from 3.4 to 3

Lulu HP per level increased from 74 to 90 Base AD increased from 46.368 to 51 Base Armor increased from 28.22 to 32

Lux HP per level lowered from 85 to 75 Armor per level lowered from 4 to 3

Nasus Base HP increased from 561.2 to 620 AD per level increased from 3.5 to 4 Attack speed per level increased from 3.48 to 4

Ornn !

Sejuani !

Tahm Kench HP per level increased from 102 to 110 Base armor increased from 47 to 52 Attack speed per level increased from 2.5 to 3.5

Vel'Koz HP per level lowered from 88 to 75 Armor per level lowered from 3.5 to 3

Wukong AD per level lowered from 4 to 3 Armor per level lowered from 3.5 to 3

Yasuo AD per level lowered from 3.2 to 2.5 Armor per level lowered from 3.4 to 3

Zed Base HP increased from 584 to 630 AD per level increased from 3.4 to 4 Attack speed per level increased from 2.1 to 3

Ziggs HP per level lowered from 92 to 78 Armor per level lowered from 3.3 to 3

I really cant find any good reason behind those nerfs like for example lux at 18 will have 250 hp and 17 armor less which sounds crazy