@MvonTzeskagrad First of all, thank you for your feedback
I think you are right about Hit From the Flank so i'm lowering the cost to 2.
Agent actually doesn't have a lot of battlecry minions so you can put The Live Bait into any deck. It was designed to be a good secret in most of the situations like Mirror Entity. As for big decks you can use Spies from the Observation Club (last week) and some generated cards from the other classes. I will definitely print more supporting cards for the big decks in the future.
I will probably change the name and art in Sniper Rifle
I was thinking about some poisionous card to help Countering Stance but for now yeah it looks weak. I will probably change the text that hero power will deal +2 damage till the end of the turn
Overconfident Agent is strong when you pull poison and weak when you pull stealth and extra strong when you pull it from your deck or hand (for example using The Live Bait). I'm still thinking about it but the randomness of it's effects stops me from nerfs.
As for the last common this is what I'm tinkering with right now
I'll do the same as MrBurger and just leave my stuff here. Then I'll just wait. Patiently. Until a feedback descends from the wise ones. Oh and @Klipce I don't know if that matters but Midnight Rager art has already been used by a Twilight Hammer token in shaman.