Both Age of Conan and Warhammer Online feature collision detection as a standard feature. In layman's terms, that means players won't be able to walk through one another, they'll push up against each other instead.

It's not new for an MMORPG, but I'm hoping that both games will be able to match their rhetoric in how this can be a useful game mechanic.

How NOT to do it:

In City of Heroes, at the lowest levels any player is able to "tank" mobs by literally holding them back, especially through doorways. That was great, but I guess Cryptic decided it was too easy, so at higher levels virtually every mob was given the ability to either fly or shoot past the tank. The end result was the same tanking via taunt-like abilities that we're used to in most of these games.

Collision detection in CoH was reduced to nothing more than an immersion tool and a way for players to annoy each other.

Let us mess with it:

When I first heard AoC would have collision detection, the scenario I imagined was one of a wall of tanks, with casters behind them building up spell weaving momentum. I'm imagining this could work in PvP too, letting the numerous barbarians and assassins smash up against that wall of tanks.

That may just be dreaming of course, the standard zerg tactics would probably give way, but even just the occasional attempt is worth it. We need this kind of new avenue for combat strategy. I hope Funcom doesn't fall in with the easy balance solutions, they should let it go ahead and be messy for a bit so they can observe and learn to innovate. It should be sandbox time.

WAR's method of collision detection has an interesting twist, it only happens between enemies. Friendly targets can still walk through each other. This sounds like it may favour collision-aware strategies, because teammate placement won't be as difficult. Your team won't have to be a well-oiled Spartan machine, but that may be a downside too, it may be too easy to defend from an invading army.