I don't think it would be a good idea to use it right now, because people barely had a chance to get 16 champs to level 2, not even 5, but later on, maybe in half a year it would be quite reasonable to reach level 2 or 3 mastery for a champ before you take it to ranked. Even if you could get there by a series of lucky wins, you still had experience with your pick's kit, damage etc. What are your thoughts?
With the current setup for ranked, no. This would be a terrible idea. Perhaps if more lower ranks were added there could be a requirement for promotionals, say 8 mastered champions for gold promos, 4 for silver, and so on it could be usable.
The big thing is we don't want people to have to grind just so they can play ranked. People are angry enough when they instantly play ranked at level 30 and get placed into bronze, but having to grind in order to earn that bronze medal would be even worse. Riot does have to run a business here, and angry customers is not the best idea.
