How feasible are ranged-based effects?

Looking at just a couple ideas for tactical composition in group play, some of the largest issues have typically relied on a immediate and lag-less detection of range in combat.

Is this feasible?

If so, what do you think could be done with it?

I'll post my own examples in a bit.

I have no idea of what you just said.

Ranged-based effects would simply be that certain attacks or weapons would have their own ranges, rather than one universal "melee range", the effects in group play being used to keep an enemy at distance between attacks so that they can't cleave the whole of your melee group.

It'd take some changes to AI and the enmity system though. In short, enemies wouldn't just gradually garner hatred against a single enemies--in fact their rate of enmity generation could be part of what makes enemy types different from each other--but also but what is strategic, or safe. A Lancer with high enmity could keep an enemy at bay (and at distance from the monster's own melee) while his teammates with shorter ranges beat on it, slowing or stunning it to keep it from reaching the Lancer and being able to attack, and then retreat once enmity shifts to a new target or (in the case that the enmity forms on a situation, not just a single damage-leading unit) drops enmity from the Lancer and rethinks its strategy. At that point a Gladiator will likely dish out its most damage possible until receiving highest enmity, aims the enemy away, and restarts the flanking.

It makes it so that a 8-ft long weapon (Lancer) acts differently than a 2-inch long weapon (Pugilist), and that those ranges can become part of strategy.

Another part that would likely occur hand in hand with this is the ability to intercept some damage by getting in the path of the strike (such as a Gladiator blocking for a Conjurer, even without an action being used), or at least better get in the way of shared-damage cleaves in order to save allies.

I just need to know if the server can handle accurately detecting how far enemies are away from each other. One of the things that scared me most in World of Warcraft was having another computer on the same network see things almost a full second after I did. If I jumped, I'd already come back down on my screen by the time I started to jump on the other. There, range-based effects would be impossible because the distance enemies appear to be at could easily vary by up to 15 yards.