yeah your right ,it also occured to me that not having tutorial push you to do things on your own and to talk with other players to share experience in game is a good way too learn and play but some players might be shy or stuff like that .
Moreover when your a total noob the game doesnt explain the different fonctions and how to talk with other players.

Regular events mixing high ranks and new players or low ranks to share stuffs and exp could be great too but regarding the actual speed of progression during the 25 first ranks ...
The problem is that you re still a noob when you get rank 20...