Archidons(Bulls Eye)
Should have an ability:
Bulls Eye-increase range

Deads(Poison guts because of the decompose of microorganisms, so body can be poison too.)
Should have an ability:
Poison Body-When die, they melt.So, they leave a pool of poison to the ground like venom flux, just less poison.

Archidons already have the ability to do long range damage? That's what fire arrows is used for. Also imagine having fire arrows with that kind of range and then putting "Bulls Eye" on top of that... you would be able to fire your arrows all the way from 1 gold mine to another in the Castle Map lol.
And for Deads having poison, it would pretty much poison all your melee units, which is irritating. I think they poison enough in my opinion (Deads, Castle Dead, Medusa Spit, etc). That's annoying enough haha :)
I like the melting idea tho, it could be part of the animation when they die, but i just disagree with the pool of poison since Medusa already does that with her spit. :)

Then archidon should get....
Rapid arrows/fast arrows/arrows of fury- Shoots two arrows simulatenously(not passive but active like fast arrows.)
Dead....
Suicide- Throws an important gut to the enemy that poisons and causes splash damage, and he'll also die.(This is for dead who had wanted to die and give a last support to the army.)

The dead's brain idea comes from Crazy Jay's development blog.

Archidons: have cool finishing move (like the old stick war game, shoot in the head of the swordwrath)
Deads: have cool looking death.