He's saying that on some site he read that Halo 2 was over rated because it was pretty much Halo 1 again with some minor adjustments. That's why it says recycled, as in, used again.
And answering his question, nah, once you play Halo 2, Halo 1 seems pointless, at least for me anyway. And you'll find a lot more people on Halo 2 on live, which will keep you busy, and the new maps added were not in Halo 1 nor were some weapons.