I've only read about half or so of the IC zerg/anti-zerg forum topics, so if this idea has already been proposed, feel free to link to it and kill this thread.

Assuming we're all on the same page that zergs in IC are ***, laughable, and make a mockery of human decency (we all do agree on that, right?, right?), what about something along the lines of this for an anti-zerg mechanic built-in by ZOS:

1a) Note: This would be exclusive to IC, not Cyrodiil at large. Cyrodiil keeps' gates require tight concentrations for key parts of the battle, so this mechanic shouldn't apply outside IC.

1) An [invisible to us] group of concentric circles is weighted around the nucleus of the zerg. i.e. wherever the density of same-alliance players in a 10 m or less radius is centred, becomes the centre of the circle. The density must meet some minimal condition, say 6 players concentrated in a 10 m or smaller radius. ZOS mechanics then places ever widening circles outward from that (again, which we the players won't see). So there's a 15 m radius circle, a 20 m radius circle, 25 m, and so on.

2) Let's put an arbitrary percentage for illustration on each circle. Wherever the amount of players exceeds 'x' within the 10 m nucleus, every same-alliance player in that nucleus gets their defences and offences nerfed considerably, and I do mean considerably. Then the next circle out, 15 m radius around the dense nucleus, the players on the margins of the 15 m radius also get nerfed, but to a lesser degree. Players between 15 and 20 m from the nucleus of the zerg get nerfed a little less, and so on and so forth. In other words, the closer you are to the densest part of the zerg, the less effective your attacks and the weaker your defences. As you move further away from this dense centre, you grow stronger in both attack and defense until at some circle, say 30 m (or whatever), you are free from any anti-zerg nerfing and are at full 'battle spirit' power. Optionally, you could also nerf TV stone rewards based on your proximity to the density of the zerg.

Just to throw out some arbitrary numbers, I would propose something as extreme as the nucleus and everyone within 10 m of that nucleus gets nerfed by 75% (drastic, but the point of this is to kill off zergs), from 10-15 m would be 50%, 15-20 would be nerfed 25%, etc. Also, the zerg would need to be defined by ZOS's calculations, so that a simple group of 4 never received any nerf. i.e. "A zerg is a group of x or more players within a 30 m radius". Anytime the same-alliance players dispersed and dropped below 'x', the nerf would immediately be removed.

Advantages:

1) It's subtle, so while 'smart' players would figure out pretty quick that zerging up makes them so weak and gives them so little reward that it's counter-productive to their goals of farming tv stones (or whatever), and stop zeroing, the 'less smart' players might take a couple weeks or months and a couple 'experiences' to realize that when they form smaller groups or move to the outskirts of where their co-alliance members are, they get way better performance and rewards. It's not in your face and doesn't require ZOS to re-teach us or re-sell us on a new idea, or muck around with specific skills. Guild leaders and community leaders will figure it out and teach the community naturally (all Adam Smith-like).

2) Whether or not it kills off every natural or artificial formation of a zerg, regardless of that outcome, zergs are nerfed without ever touching individual skills or trying to balance the classes, since the attack/defense nerfs are universal and not 'Magicka' or 'Stamina' specific (or whatever). As such, groups of 4 (aka 'not zergs') and smaller can actually take on these comical 20+ group zergs and wipe them out in God-mode. Community corrects itself. Zerg disperses so as not to be wiped out in God-mode, and individual 'ex-zerg' players feel more buffed and level with the group of 4 as they disperse.

3) The minimum 'x' amount (it's 6 players in my head, but whatever you like) is higher than 4, so no nerfing of 'real groups of 4' ever occurs, and when solo 'yokels' like myself think they're lending a hand by photo-bombing a group of 4, there's a little give so that the group of 4 don't get nerfed if one or two extra players join the fight.

Disadvantages:

1) Accidental overlap of independent groups of 4 plus stragglers can nerf themselves despite having the best of intentions. Group leaders, though, can probably self-correct this without too much need to be geniuses.

2) ? (your thoughts on why this idea is flawed)