That's where I personally disagree. Not saying it requires a huge amount of skill, but it does require some. I have been playing Halo for over a decade with the same two friends and they don't use the radar at all (they, like a good amount of players, lack the eye coordination to play and keep an eye on the radar at the same time), even though they are good players. if they used it, they would perform a lot better. keeping a half eye on the radar prevents a decent amount of deaths and makes you more aware of enemy presence.
The radar is a tool, and you should use it, but you can't rely on it. That's true. If you solely rely on your radar you will indeed get killed by people abusing that fact. I just think they kinda sabotaged the tool this time around in arena. Like giving you a hammer with only the staff, but not the head.
Ooh well, good thing I have a good headset and can often hear people even before they come into radar range
EDIT:
How so? People that crouch camp do this to catch their opponents unaware and gain an advantage. Why would they suddenly stop doing this when there is no radar at all?
I mean, nothing changes for the campers? they remain undetected, radar or no radar.