We've all been a victim to some coward hiding around a corner with a shotgun or some sniper who finds some weird vantage point to pick people off. It's a cheap, despicable exploit that ruins the gameplay. Yes, I am talking about campers. They ruin the game. But this is a problem that could easily be solved if bungie put waypoints above everybody's heads. That way nobody will get the drop on you because you will always know where they are. I remember the 1v1 playlist on halo 3 had a similar mechanic, but I'm surprised this hasn't been utilized more effectively.
I think this would be well implemented in certain game types. But not all game types. Sometimes camping for a SMALL time in a spot can really make the difference between holding a certain point, protecting the flag, etc. Though game types like Relic could use this since the main idea is to hold a position and everyone is going there anyway. Though that's neither here not there at that point. In all honesty learning a map over time and knowing "hot zones" really does away with the need for your idea. And "hot zones" are things that are in ALL FPS multiplayers.