I see no reason to consider changing ranked to even allow for the option of collection only. The whole point of a competitive ranked PvP mode in ANY game is to provide an experience where players can use their skill to outplay their opponent(s) and obtain rankings based on their demonstrated skill. Once you have outside influences giving one player an advantage over another before the match even starts, it begins to trivialize any showing of skill, thus the "ranked" aspect is pointless.
I get that quite a few players enjoyed the fact that you could grind for a maxed out PvP deck and then stomp people who didn't put in that same effort, but this kind of gameplay only heightens the enjoyment of the players on top at the expense of those at the bottom.
Now separating the playerbase into brackets based on deck level would make these issues less apparent, but they wouldn't be removed completely. It would also be pointless to implement currently as there aren't enough players to consistently have matches in each bracket.