Personally, although magnets and duplication are useful, I far too often find myself turning magnets on and off repeatedly because they can get very annoying more often than not. I wish we still had precision editing because doing asthetics is a pain now. I wanted interesting terrain to forge, I thought with the original 3 forge maps we had plenty of space, but we get even more boring terrain in halo 4. Most of my complaints about halo 4's forge however are in the gametypes. It's hard to make good custom gametypes for maps without insane, zombie traits, etc. and some of my favorite gametypes (invasion, 1-flag, race, insane, assault) have been removed