If archers had the ability to deploy stakes. Basically wooden spikes in front of them. If cavalry charge into them they get instantly killed. How would this affect game balance? To make it more balanced the archers can’t move and it takes awhile for it to be set up. Once the archers move, the stakes disappear. It’s free to set up stakes.
Or perhaps a special unique unit could do it?
I think it’s a bad idea to change them this way, as aoe2 isn’t a game about activated abilities. It should stay in aoe4.
Yeah, it would change the game in way. But also, add a defensive ability on very open maps. (but also very powerful on closed ones) Still, I think you may be right.
AI might not be able to handle this so it would be an issue for scenarios.
I can see activates abilities in aoe2 without breaking the game balance or making it too gimicky, but this isn’t one of them.
But the question you really need to ask yourself is this. Do archers really need a strong cav counter? Will this make the game better? What impact will it have on traditional cav counters? How do you balance it so cav civs still have options vs archer civs?
Yeah, the Persians for exmaple would have a hard time. They would such really bad here.
Late game Britons, 3 trebs with warwolf + ~60 archers, all with maximum range and spikes protecting them, maybe in box formation. Some vils building a forward castle next to all this. How would you defeat it? xD
That is such a major change to the game, you can’t do that to a game that ppl have been playing for 20 years, that’s my 2 cents 
Unbreakable. But it could be cool to see in a scenario.