You change the assumption by being specific in your description of how your character acts. Characters are assumed to stand on two legs, but you can specify you character is hopping.
you are voluntarily blinding yourself (with all attached) to every other direction.
...and should grant CA to every foe who isn't in the direction you're facing, I would say. If you want to go for cheese, punish'ed be thy name.
Now, on that note, if you're concerned about the technicality that a ranger could have a situation where he has 2 bad guys...one is 3 away the other six but he wants to quarry the further one...so he moves behind a column to give the one 3 away total concealment so that he cannot "see" the nearer one and thus the one six away is the closest he can "see", this raises the question of whether this is concealment or cover...and does awareness count as seeing? And is taking that time to move to gain cover worth it? and do we care if the ranger is able to switch out his quarry like that?
DC
No, you -can- see around you. Absolutely nothing is stopping you from using the ancient art of turning your head. Line of sight is not disrupted by equipment you hold in front of your face, when said equipment can be moved almost as easily as your head.
From how you continue your post, I think you are...I'm not even sure what you're asking here...
True. But a 4E Ranger is encouraged to move in ways completely contradictory to common sense, having some bizarre supernatural ability to hurt some people but only if he can't see other, closer, people; even if he knows they're there!Terrain isn't metagame...in combat of any era, terrain factors massively into tactics...your ability to see or not see someone (and conversely have them see / not see you) has a huge impact.
Involving cover and concealment would only make a big headache grow into a monumental pain in the ass.Now, on that note, if you're concerned about the technicality that a ranger could have a situation where he has 2 bad guys...one is 3 away the other six but he wants to quarry the further one...so he moves behind a column to give the one 3 away total concealment so that he cannot "see" the nearer one and thus the one six away is the closest he can "see", this raises the question of whether this is concealment or cover...and does awareness count as seeing? And is taking that time to move to gain cover worth it? and do we care if the ranger is able to switch out his quarry like that?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.