R cool downs balance change

Dear riot I don't understand how you say you don't like when people have insanely low cool downs when people like lux and Leona can have up to 30 second r's and lux r mid to late can deal up to over 500 ability power and Leona r can stun entire teams and deal 250 base ap and both these r's can have insanly low cool downs.For very easy spam so please maybe you should consider increasing the cool downs on them. And with that you shouldnt just generiically say that there r's arent as strong as others. Also why can these champs have that cool down and karthus is still at his 200 second r cool down.