Ways to balance adcs and tanks

Tanks: Building Hp (full item) reduces your ad/ap by 5% (15% max). Building armor (full item) reduces your lethality by 2.5% (10%). Building damage (full item) reduces hp by 5% (20% max bonus hp). Building lethality (full item) reduces your armor by 5 (max 30). Vice versa mr and ap.

Adc: Building armor (full item) reduces your ad by 20. Building hp (full item) reduces lethality by 5%. Building ad items subtract total armor/mr. 12 armor and 20 magic resistance taken the maximum. Building lethality (full item) decreases 50 hp (but will not die on purchase). Max hp loss, 300.

Anybody building ^ that stuff above is subjected to effects too.

Ap costs too much gold.

One way to balance out the bs would be this method. Making sure each champion is in check, making hybrid build reliable still but making sure it doesn't snowball out of control.