In your opinion, who is the worst champ in the game to firstpick?
My vote goes to 
x-post from GD
My vote goes to 
x-post from GD
deserves an honorable mention. This is the only champ that I have personally been flamed for first picking. People know that she's easily counterable; that may be less true since her rework, but I'm still nervous to pick her blind.

Yi. Any CC counter pick knowing how to play vs YI make his life unbearable.
Lol @ people thinking Ahri's an unsafe blind pick.
She's one of... if not the safest blind pick mid laner you can play in solo queue.
Garen or trundle
Picking
at any point
probably
In my opinion, this guy:
(Note: of course, this is biased, since I go after my personal experiences)
Since he doesn't have any dash and can just deal significant damage behind himself, I get the feeling that if you first pick him, then the enemy will simply pick someone you can't reach on your own and therefore you are not able to pressure them in any way.
without a doubt.
His kit just screams "pick a long range mage or any assassin" Which are both extremely popular. It's nice that we get counterplay, but 90% of the popular roster shouldn't be able to shit on one champ.
Sure he had presence in pro play but then he was nerfed probably because it wasnt fla$hy enough.

First picking her usually means the enemy is going to pick
.
It's unlikely you'd be able to get all 3 banned as well.
Eh, kog gets hard countered in every game nowadays purely by accident. If anything first picking him incentives your team to pick around him.
probably. Easy to counterpick from any lane.
Any Tank in the top lane.
Going against ranged champs or Illoai is hopeless. Also, playing against nasus is awful when you first pick a tank. He free farms stacks in your face and there is nothing you can do about it. You are at the mercy of your team because your lane is already lost 1v1.
Kind of have that same feeling vs vayne top as a tank but at least vayne has a harder time 1v3ing your team while you are unable to do any damage to Nasus.
I know I mention Nasus a lot but he isnt the biggest offender. Illaoi is way worse
Darius in a decent Elo, where they will just spam ranged Toplaners.
for my money, i'd have to say
. he has nothing in his kit to deal with anything. he has no real way to close a gap but he really struggles against tanks. also he is completely defenseless when barraged by ranged harass.
Azir. I'm sorry. I love the funky chicken but he's so very bad.
No real need to post this a second time, it was fine in GD... But my response from the other one:
Teemo is a pretty rough first pick. As is Aurelion Sol. Either one of them is going to end up hard countered if they're first picked in their "Usual" roles.
When I see someone first pick Kog... I'm like oh god I have to pick lulu or some type of heal peeler or we're screwed.

.
Has the most lane specific hard counters of any champion in the game (even top).
Hence why I generally only play her for fun in Norms, or as Support, or jungle.
Rarely play Ahri in ranked, even though I'm 57% with her.