You should require certain mastery points to play champs in Ranked, much like Smites mastery system. it works like this (or at least it did when i played in Season 1, start of Season 2)
Gods have mastery levels going to 10. You need X amount of Gods at mastery level 1 in order to even queue for Leagues(ranked matches)..
Then, if you meet those requirements, you cannot play gods IN LEAGUES unless you have the god you're selecting at Mastery level 1. This system ensures you can play the god you're choosing (at least at a rudimentary level, the amount of games it takes for mastery level 1 in smite is enough to make you understand, Nemesis'((shes my main, hence the bias)) for example and play her on a rudimentary level.
So not only do you require basic knowledge of X amount of gods(i think its 12 Gods needed, although it might have been 16) you also require that if you want to play certain gods(in the case of my example, new gods) you MUST practice with them in normal games and acquire God Mastery points and achieve rank 1.
What my point is, this system could be beneficial to League, because it certainly alleviates a lot of new character lock ins and "oh X is broken I'll just choose him even though I've NEVER play him" from champ select.