I liked exploring in Halo 1 more because you found stuff they didn't expect you to find or ever even get to. But now they were pretty much just sitting in some conference room going, "Okay guys, Outskirts is a pretty cool level now lets put a trash heap here so they can jump to here and then to there and lets put a light here that is conveniently just big enough for you to stand on." Magical. Isn't it? In Halo 1 I don't think Bungie really expected you to find Pvt. Whats-his-name on 343GS, they just put him there cuz they got bored.
And these invisible walls are just annoying. I believe it is within my basic human rights to be able to jump off of the edge of Outskirts and fall until the sun goes supernova