I think Janna has an interesting win rate problem in that very bad/new and filled players will max e, making it look worse.
Many challenger players will still go for e max (often after 2 points in w) and dream maker, but it's less common than the "fun" w max build
You also are more likely to pivot to e max if you are losing, if you have died 2-3 times pre 6 it's pretty troll to continue making w
Yep that's also valid. Players shift behavior, which can't easily be cleaned up when just looking at performance from the outside.
If you're slamming as an ADC, you don't bother counter-building Soraka. If you're losing, you may as well buy Executioner's and then you may as well finish Mortal Reminder at some point.