Personally, I haven't experienced an increase in toxicisity in the game. Maybe about once every month or two someone will go off the deepend in the game or send me a private message. Generally, everyone I play with are either quiet or friendly. I could be just lucky.
The hardest ones atm are maldamba, ying and grover because of mechanics or positioning just pick those when you are more experienced. Also pip and grohk are not in a good place as support (they are decent as damage dealers though).
Seris and jenos are the best champs for a starter
I disagree with Grover really being difficult with how he plays now, but this pretty much.