You want to increase janna skill cap?

"Coin's definitely a significant part of Janna's current strength and we'll be hitting that. Possible Janna's also out of line as well, planning to look into her, both from a balance perspective and to determine whether there's some quick work we can do to add some more moments of skill expression to her kit as well.

In terms of 'best support in the game', I think some of that also depends on how you define best support. She's certainly right up there at present, historically she's often sat at a really high win rate, without actually being as strong as that might suggest, because of how forgiving her play can be (e.g. first game Jannas are likely to be much more useful than first game players on most other champs in the support position)."

So meddler posted this in his dev corner and next janna nerf will aim to give her more skill expression, in order to reduce how well a new janna player can do

if you want to do that then you need to make her less forgiving

you already did that in the past by disabling janna's passive on herself E cast range should reduced massively to make her less forgiving base ms should be decreased for more ms on W passive Q base knock up should be decreased to punish players for not using it to stop dashes

ect....