I didn't try it, so I'm just speculating, but Archer seems worse to me than Coil.
Ok, I mean, if you go with things that "one can do and other cant":
Archer:
Can pop shield and leave 1/1 body. (best vs Sunwalker)
Can activate Amani and leave 1/1 body. (though I only play 1 Amani)
Can shoot face.
Sometimes you have Coil and Doomguard/0 mana burn in hand and you don't really want to draw as you are going to discard that card anyway.
Coil:
Efficiently makes your deck 2 cards thinner (Flare effect) and can more dig for that one card that you need (Doomguard/burn/Wolf/Sargent usualy). With hero power, you can dig for 3.
Can kill your own creature when you know your enemy is going to board-clear you to draw and card and get rid of what is usually a bad card in such matchups.
So, Archer seems to have a bit of a edge, but..
If you ignore these edge cases, and go for the primary use of the card (finish 1 hp enemies) which you do 90% of the time.. Coil wins hands down IMO.
I mean, Archer seems to be like a Coil that always draws WISP. And I don't want to draw wisp almost ever. You want to draw your strong cards.
Your comparison with Paladin/Lock powers is wrong -this doesn't cost you life, and Lock power IS WAY better in your deck, as your deck is made to abuse that power and to be able to put 2 strong cheap bodies each and every turn. Coil allows that. 1/1 is not a strong body.
And this is way more important that the little bit of versatility that Archer gives, I think.
As I said, this is without playing the card. I might try to to play it and prove myself wrong, but not sure. (I also didn't like Mukla in Zoo, FWIW).