You will commonly find gank groups in many PvP games. Gank groups are simply organized, pre-made groups, usually formed by members of the same guild that work extremely well together. Usually, a gank group will destroy a pick-up group (PuG) and zerg because they employ smarter tactics, keep cooler heads, and communicate more effectively.
Gank groups were very common back when I played Dark Age of Camelot from 2001-2004. These 8-man special-ops teams would sweep in at high speed, disable as many enemies as they could with crowd control, and then quickly pick off targets one or two at a time. Most PuGs and zerglings would panic, which made the job that much easier.
The true challenge would come when your gank group met an enemy gank group in the open field. The outcome would come down to a combination of skill, gear, timing, communication, ability timers (realm and master level), and even luck. Taking part in a gank group vs. gank group skirmish was probably the most adrenaline-inducing MMO experience I have had in an MMO and one I have been searching for in every new PvP MMO I try.
My most recent hope was for Warhammer Online because Mythic's latest RvR MMO was supposed to be the spiritual successor of DAOC. After playing the game for 7 months, putting some thought into it, and chatting with friends, I've come to the conclusion that WAR is not currently designed to support gank groups.
The biggest rewards in WAR come from sacking objectives and pushing the RvR campaign forward. You get the most renown, influence, gear, and tokens from taking BOs, keeps, fortresses, zones, and cities. Considering gank groups are more interested in player vs. player challenges rather than player vs. objective/environment, this is a big disincentive. The end-game of city capture and the mass amounts of PvE that take place in all stages except the first leaves them questioning their end-game purpose.
The next big detractor is the prevalence of zerging in WAR. Zerging took place in DAOC as well, but there is a key difference: gank groups actually stood a chance vs. zergs in DAOC. They do not in WAR. AoE crowd control and direct damage in Warhammer is much more debilitating than it ever was in DAOC, which is quite an achievement considering how bad it was in the latter. An 8-man group stood a chance vs. a 24-man zerg in DAOC by ambushing key targets, using superior tactics, gear, and skill, and maintaining mobility. A 6-man gank group would be completely annihilated versus an 18-man warband in WAR because once they ambushed they would eat stuns, disables, roots, silences, snares, knock downs, knock backs, and disarms in very rapid succession.
You also have fun-factor issues for gank grouping in WAR. Even the smallest servers in DAOC had roaming gank groups or 8-man PuGs for you to fight. In WAR, people either run in a zerg or in very small groups of 1-2 players (trying to catch up with the zerg). It's no fun massacring a smaller group and you stand no chance vs. the zerg. That means the only real fun you could experience would be going up against other gank groups... but due to all the current disincentives, there aren't (m)any. Hence, gank grouping is not fun in WAR.
Continue reading for conclusions and suggestions for improvement.