I don't want to be that guy, but...
I've seen Janna so much in the last few days, picked her too when I was autofilled support, and I was like "hey wait why is Janna so popular?"
Then I went on LeagueOfGraphs and... holy shit, 22% play rate and around 56% winrate in plat+, INCREASING in dia+ (like 28% playrate).
That coin buff really helped her a lot, maybe too much. She can get ardent before the enemy support gets sightstone+boots.
Is it really only because of coin or is Janna busted again, despite receiving only nerfs for the last 3 years? Lol