Since Eazy seems to be slacking here with some anti hype, I'm going to have to step up to the plate.
While the fly through of forge world is fantastic, how much does having this as one huge map actually add? Are we going to see any good maps that jump from one space to the next? Probably not, that's just going to end up with game play that's too scattered for it's own good.
The other problem with putting a giant forgeable world like this together is the visual palette and objects have to be the same. Every single forge base map will be made with fore-runner pieces on the ringworld. Visually that's going to get boring eventually. Bungie mentioned that this was originally 5 totally seperate maps, and I think 5 maps, with 5 full object palettes would have provided more variety, while not losing very much.
Which brings us to the other issue, the overall variety of maps. 9 total unique maps, 2-3 of them will end up as invasion maps, 1 is Forgeworld, and that leaves us with 6-7 maps for classic halo gameplay. If you count all the various unique Forgeworld variations, you are looking at 11-12 on the disc, with 5 of those being visually identical.
On top of that the game feautures 4 remakes, 1 a full a remake and 3 forge remakes. With this few maps, if any of the core maps is the next Isolation or Epitaph, it's a big issue. Considering also that Sword base got mixed reviews (I enjoyed it though...). Make that doubly so for invasion, which looks to be sporting very few maps come launch. Even further, how do you specialize the maps with so few? Already looking at the list there's a major shortage of arena style maps, and a bounty of 1 flag focussed maps. There are maybe 3 revealed so far that could even remotely support 2 flag CTF (Gulch remake, sanctuary remake, and zealot).
It really seems like Bungie is hoping to forge their way out of this map hole, with a 5 forged maps out of the box (I'm not counting the griffball court :lol ), and more to likely hit shortly after release (with wizard and lockout remakes being shown) it seems we are in for a lot of fore-runner archictecture sitting on green grass.