I'll go second then.
In general, I expect nerfs to burn, or buffs to ways to counter it. Nothing specific in mind really but the deck needs to be looked at.
Ezreal and Karma, one thing to be careful about those 2 is that they synergize really well together. They are both great in other decks, but the biggest issue is when they are paired together. So nerfing one of them might affect how often you see the other. So Riot has to be careful if they nerf both.
Ezreal: I agree he needs to be looked at, he has been on the watchlist for a while now. I think reducing the ping to 1 would kill the card, what I'd like to see is have his text be something like "The first 3 times you cast a spell this turn, deal 2 to the enemy nexus." It keeps the burst potential to some extent, but limits how much can be done in a single turn giving the opponent more time to counter him.
Karma: Like Ezreal she also has been on the watchlist now for a while now. I'm not sure increasing her cost would do much, it might slow the shenanigans but she would still be able to do everything she does already, also she is often best played at the end of the opponent's turn for full effect on your turn with full mana. I would prefer to see some restriction on the spell that are affected either by spell speed, like only affect slow, or fast or burst spell, or by spell cost. Just limit what she does, in her case more costly doesn't solve the problem I think.
Unyielding: I've said before that this card is awful. It's too much of a binary effect where you can deal with it, and it's not an issue, or you can't and you most likely lose. This type of card should be a meme card to be honest. Or introduce more ways to counter it. Personally I think it shouldn't be castable on Champions. There's too many ways this create a terrible situation, maybe reduce it's cost and make it castable on followers only. The impact is less on a follower, and allows for Purify as an added counter.
Boomcrew Rookie: Yeah, the 3 health is most likely what we'll see.
Draw from Opponent: I don't think the mechanic need much change, drawing from bottom of deck would make sense since drawing cards from your opponent is already a big play, but drawing buffed card is kinda double dipping effect, where you not only steal a card, but get to play a buffed card. It also targets Freljord a lot which is one of the weakest region.
I want to see Vladimir buffed the most, he's such a cool concept but so weak right now. I'd like to see something along the line of "Attack: For each other attacking ally, deal 1 to it and
DRAIN 1 from the enemy Nexus". Now on a full board draining 5 might be too much, but the effect is counterable in many ways so it might be ok.
All in all to be honest, I feel the game is mostly in a really good place. Just nerfing burn would open up the meta a bit. The risk is obviously Control getting out of control without burn to reign it in a bit.
I think the focus should be nerfing burn, the deck is way too efficient, cheap to make, easy to play, and so fast for ranking up. It doesn't matter if you lose some, you play so many games so fast that you'll rank up faster than other slower deck with higher win rate.
The second thing is Freljord, poros are a meme, yetis are not competitive, ramp isn't really working, and right now it gets the buffed card stolen. That's like 3 theme of the region that are not working. Frostbite is the best thing it has, but often lacks follow up, sure you delay the game but it lacks a strong closing strategy.