Players do not play for you.
This is my main point right there. And stating risks in playing these picks is absolutely a part of my point. Flyquest is the #1 example of a team willing to take those unorthodox picks as they've done week after week. Faker himself said in an interview last season (around the Galio pick he pulled) that all champions are viable if you can make them work. Just because any champion is capable of being viable doesn't entirely mean they are absolutely win securing, which matters to these competitive teams, especially the ones that are struggling or just wanting to remain on top. The only exception is when there's absolutely nothing left to fight for: example shown by Team Gates Allorim, a well known Wukong player who didn't play the champ at all until the very last game when there was already nothing to lose.
League as a competitive scene is not always the same 20% picked/banned all the time every game and you know that. A post like this is no different from what's been posted for the last couple of weeks when it started out as "Same bans, same bot lane, etc" and normally those thread posters failed to really look into what kind of picks have been picked aside from what they watch.
If NALCS is your only sample to make that complaint, then that's pretty inefficient research on your claim of "lack of diversity" on a major region scale. And even still, if Riot decided to gut the top 20 used champions competitively at mid season, that would only recreate the tier list and you'd wind up getting those champions game after game until someone got bored and would make another whiny post about it. At the same time, it would potentially throw casual play into disarray. Who wins from that: the viewers who want diversity but don't play the game or the viewers who want to see diversity in the form of different champs in roles only to imitate it when they could do it for themselves any time they really felt like?
As for "lacking variety", pro play is not casual play (SoloQ included). My points above explain that. And with that, no I don't think it sucks at all. I've watched other competitive games with 50+ characters and only 10-12 get used. This is nothing.