If 343 sets out to make a traditional Halo game (e.g. Halo 1-3/Reach), hopefully they add in support for fully integrate-able DLC content like vehicles or weapons or abilities, as well as allow weapon-specific properties to be tweaked (e.g. set DMR damage separately from AR damage, tweak sticky grenade detonation time, frag grenade blast radius and falloff, enable/disable shield bleedthrough with melees, separate melee damage options for health and shields, that sort of thing). It would've been nice if Classic settings could actually emulate the classic games without needless quirks like overpowered snipers and grenades or DMRs instead of BRs.

It would just be so cool to load up Halo Reach and have (essentially) the Halo 2 experience, right there in the playlist options, tied to the modern interface, armory, credit, and stat-tracking system of Reach. Hopefully 343 will be less stingy about maps too.

Either 343 is going to go in a new direction with Halo (risky, might lose older audience, might gain newer audience), or stick with what works (if people keep on buying CoD when each year brings minimal updates to the formula, they'll keep buying Halo too). If 343 goes with the latter option, either they will have to come up with some innovative twist on the formula (such as Halo 2's dual-wielding, Halo 3' equipment, or Reach's armor abilities and loadouts) which will be hard to do, or they'll have to give players more modes, gametypes, settings, weapons, vehicles, and maps to play around with.