@Riot, thoughts on Ahri
I understand why you're changing her. She is much stronger than people were expected. This nerf is expected.
But I think you're going about it the wrong way. The problem is that everything she needs is loaded into her Q. -Waveclear -Poke -Mobility -Sustain(the healing she gets from her Q far surpasses her other abilities) -Damage(280 damage +70% AP, half of this is true damage, although this damage has plenty of counterplay)
Take the MS boost of her Q and put it on her W. This will cause her to use more mana in the laning phase to keep using her movement speed. Currently it's not an ability she has to cast often. This also puts her MS on a slightly longer CD till she ranks W. Unless she ranks W first(doable, but rare case vs certain champions).
I haven't done much to play Ahri lately, even though I was excited to see her being turned back into a mage(I never enjoyed assassin Ahri). But it is my understanding that she does fall off late game fairly hard right now. Lowering her damage and increasing her mana costs don't really sound right. I could be wrong of course. Her win rate does show this. But I don't think it will fix the actual problem. It'll just make her feel clunky.
J4 is also a part of this "loaded single skill". HIs Q -Damage -Poke -Armor Shred -Mobility combo with strong CC, max rank can allow for two Q's per flag
Compared to his W/E it's the obvious first one to max. And it's fine to have an obvious skill to max first. But there is far too much power in this skill. I would say tie the armor shred to his W. This would delay that power spike till later in the game. And he can rank it second as an option if he wants the damage over his E for the AS/armor. It could also be tied to his ult similiar to Sivir's AS boost on her W.