4th Mastery tree just for supports?
Just like gold generating items provide good stuff for supports, because they are usually not worth to buy on laners (except for spooky for short period), we could have supporting tree. Right now we can't i.e. have vision enhancing keystone in Cunning, or better version of expose weakness, or mastery granting you mini-version of Leona's passive to make supports more relevant, because everybody and their mother would take it.
BUT if such masteries required you to dig dip into say Assistance tree, making you pass on assassin, dangerous game, precision and all of that if you want it, maybe it would be doable.
Thoughts?