Coming out of the thread on cursed items, had some thoughts about neutral critters. Usual disclaimers, Sorry if already talked about or im tossing it too early/late, such and such.
First on Really neutral critters.
Being able to actually create neutral critters would be nice. Make a troll, then turn it loose in some other empires back yard. You don't pay upkeep on it, you don't control it, and its not flagged as being yours. All you did was make it and send it forth to wreck bloody chaos. This could let you mess with someone without actually having to declare war. If a zone is contested you could make some pretty mean critters and turn em loose in the area to keep others back. And since you are not paying upkeep on the critter you can afford to go all out and really make some vicious stuff.
This could let you get involved in a fight that you can't actually afford to commit yourself to. Obviously, if you release a neutral troll in the middle of a border between you and some other rival, he can figure out it was you. Unless that kind of critter appears in the area naturally, then it might be a bit harder. Or if you released a critter that hapenes somewhere naturally, and there are 3-4 borders right near there, no one will be able to point to you as the culprit. This could let you strike at someone without inviting retaliation.
Although when releasing these critters, you would have to be worried about them heading straight back in and attack your own troops too. And if the person who kills it has the body brought in for examination and has teched Troll Anatomy and Physiology or Magical Forensics, then he might be able to figure out who made it.
What these things had to do with cursed items is, if you could make a neutral critter and put it in its natural habitat, and put a cursed magic item on it, if a rival hero kills the critter, he is pretty likley to use the item since the critter looked like it was there naturally.
Second on Faking It neutral critters.
In civ4, i loved the privaters. They were gunpowder era ships, fairly weak, but with one important distinction. They were not flying a flag. They were always colored grey, not thier owner's color. You could use them to attack other nations without declaring war. They were weak enough that they could not pose a serious threat to anyone, but they could very annoying. Obviously, other players could see through it instantly since they moved on thier owner's turn, but with simultaneous turns, such things could be pretty useful.
Not just ships either, back in the middle ages, when a knight wanted to go out and commit dastardly deedsor other actions he did not want attributed to him would cover up or blaken thier coat of arms to prevent identifcation. Having a few units capable of such things would be very intresting. Want to weaken someone, but can't afford a war with them? Grab a unit of brigands and send them across to pillage and raze structures. Want to support another nation, but can't afford to antagonize thier attacker? Send in a team of loyal knights who are willing to strip any identification off themselves and send them in to fight. Or even better, make a secret deal with another channeler to send your blackened troops through his land to attack a mutual enemy. He can claim they just slipped through, you can claim nothing to do with it.
Of course, only a few units would actually be able to pull this off. Brigands and highwaymen would be naturals at it, plus they would be able to sneak around, but they are not exactly the finest fighters around and are likley to lose any serious confrontation. On the other end of the spectrum, you can have the elite knights, completly loyal to you, would die under torture before revealing who they serve. They would not be the sneakiest, but they could pack a punch and keep that agressive empire from the north from gobbling up your weaker neighbors.
Or the most sneaky case. Say you have a weak northern neighbor. Beyond him lies a large aggresive empire. You like having your weak neighbor as a buffer and don't want to spend your resources constantly fighting along that border. However, you can't just ally with the neighbor, that massive empire might come after you. If the empire sees a sudden influx of knights without flags in the weak neighbor, it dosen't take a lot of thought to figure out who is sending them. So you make a secret treaty with your neighbor. You send some of your loyal knights north to the border. But instead of usng blank shields, your neighbors lends them his colors! The border holds much better with your knights there, the empire is clueless as to your involvment, and you are only paying for a couple knights to keep it that way. Your weaker neighbor has his border secure, but now he has powerful knights loyal to you mixed in with his troops. A very dangerous situation for him.
Having some flexiblity in troops identifying themselves could be incredibly useful and create very intresting situations.
Anyway, my 2 cents.