Whether something is "viable" or not is highly subjective and very much based on your opinion of the game and the context with which you see it. For instance, I do not personally like to play support if my ad carry is playing
, but not because she is a "bad" ad carry. I don't like to talk about balancing from that perspective, simply because I know my opinion is too subjective and I don't keep up with the pro scene/stats in general to have a good opinion. My reason for not liking to lane with her is because she is very different from any other ad carry, more akin to an mid lane caster, and I have to play very differently in response to that. However, I have also seen plenty of good
players that were able to take advantage of her toolkit to genuinely carry games, and even if I might not be the most comfortable playing alongside her in the laning phase, I won't force someone away from their main champion.
By trying to determine what is or isn't "allowed" in ranked beyond just the bans we currently have, I feel that would only cause an even more strict meta to be enforced. Now, not only are you not allowed to deviate with an unconventional build or laning strategy, you aren't allowed to play certain champions because they "just do not work" for whatever reason. You mention
, and about how annoying she was pre-rework as a mid laner and how weak as a support, but back in the middle of season 3, she was also the primary champion I used to climb up the ladder, using a similar strategy. By utilizing her free harass and attack damage marks, I could outlast the enemy early game, and bait out the wannabe gold assassins that thought they were the best thing ever. For what I ran into at Gold, despite being in the "bad" role for her according to many back then, she got me into and through most of gold in a time when I was still reeling from the
nerfs. I definitely had people who told me not to, and there were a couple of times in which I didn't budge and we went on to win because I had gone a certain pick. The reason it took me so long to even find
as my main champion was because Soraka was so good at shutting her down early on.
Trying to artificially limit the champion pool available in Ranked is counter-productive. In doing so, you create an issue of whether or not they actually are viable in Ranked, as it's harder to conclude anything about balance from looking at normal Summoner's Rift alone. It's definitely annoying when someone picks someone who isn't as "good" and does poorly with them, but it's through trying new champions and eventually running them in Ranked that we determine whether something is good or not, or more importantly whether or not we are good at that champion in that role. We already have a strict meta as it is, why should we make it even more artificially strict, or try and force someone into a position where they aren't as comfortable and won't play as well? I can imagine very few scenarios where artificially limiting the champion pool, apart from when a champion has a gamebreaking bug that needs to be fixed, is ever a good thing overall.