Yes and no. On one hand, aside from glitches/exploits, I'd consider Halo 2 to be fairly balanced even by today's standards. On the other, I think a lot of progress has been made since Halo 2, and replaying it wouldn't be the same. I'd love to play Halo 2 online multiplayer again, but it would probably just be for a short stint.
Halo 3 is a different story; if I could temporarily trade every other multiplayer game for 6 months to play it in its heyday for one month, I'd do it (I know, that is a goofy hypothetical xD).