@[RD]Godde and I played a few games.
B195146 2 on Red CometThe first game, I just reasoned regarding the two weaknesses of the Archer: High HP units which waste its tank, and homing high-alpha skirms which can hit it even if it pushes them away (In fact, this helps them to kite!).
So, halberd and scalpel were the natural choice. As it happens I didn't even really need to make it to Scalpels, exhausting his archers alone meant he couldn't raid me, was stuck in his base, and I could snipe his eco with Halbs once the archers ran out. One closed Halberd can drain 3 Archers.
It became a bit harder when he switched off of Archers to Bouy/Duck, but I was too far ahead and won that game. Rare that I can take a game from Godde, so that shows it's a very strong counter, which he agreed with. That's only one factory though.
So I tried shieldbots:
B195152 2 on Archers_Valley_v6I figured I could do a similiar thing to Halberds as I did with Zeus, but it just didn't work. I thought with their range and accuracy they could hit the archers, but they just got pushed around and didn't have the HP to drain their tanks. I switched to Scythe, which did a lot better and got into his economy several times, figuring that with Scythe I can get in range and hit, and if he pushes me out of range I can just cloak again. This worked for the most part, and I think could be viable, but by then it was too late. Worth noting: I was ahead in eco the whole game. The Archer in the bottom left who dies to an in-construction LLT and the con assisting it shows how poor of a raider Archer is, and with it's slower speed and high cost it's coverage is poor, so I could really expand aggressively. But he got army advantage and Archers scale really well with other archers, till the point he could take out my comm, and by that point I didn't have the static defenses to stop him.
I still think the correct counter is to slow down his eco and expansion either using Scythe or Glaive (Glaives just avoiding his Archers, since they're faster and cheaper for better coverage), then expand with LLT's yourself. Edit: It's also important to spam solars, archers can kill winds, but solars waste their tank so bad. If you can take out his buildings and he can't take out yours, you out-eco him, but dealing with that big mid-game Archer ball is still going to be hard. Burrowed ticks?
Anyway, there are counters, I don't think it's OP. But it also has no synergy, stacks only with itself (and grizzlies), is good against almost every class of mobile and is annoying to fight against.
Godde raised the point that it had good synergy with old duck because the duck was like a mini-scalpel. You'd get your high alpha shot off, then push the enemy away while you reload. I think this means the duck and archer have better synergy, but it also gives them the same role (Since the archer and duck both can be 'shot wasted', are both good vs mobiles, etc). Either way I think the Archer probably needs it's range to go down to at least the range of a conventional riot unit. Then skirms become a much more obvious counter because pushing them away just helps them kite.