You shouldn't be allowed to use a champion for the first times in ranked
Most people have the common sense to try a champion out a couple of times in normals before they bring them in to rank,
But how many times this has happened? People buy a champion and isntalock in ranked, thinking they are capable of using it, then feeding and basically condemning your team.
Shouldn't be there a rules that say "Before using this champion in ranked matches, try it at least 5 times in normal games"?