" Dynamic Queue has greatly lowered toxicity in ranked "
For who? Because playing solo with 3-4 trolls or people who are just as toxic as they would be back in solo queue sure as hell is not an improvement. The only difference is they use eachother to justify being douchebags. People didn't miraculously change behavior because they could play with friends, it more often just puts more toxic people in the same match because they knew them from X, and then proceed to treat other players like shit regardless.