-About 3-5 new quests which can lead you to new weapons and items
-New buildings and map markers
I'm gonna keep it very vague for now. Here are the old features we're keeping/modifying
-A greener world with living trees and no lingering fallout (except in certain quest areas)
-Destruction effects such as being able to shoot a box of ammo with explosive results. Not exactly realistic, but it is very fun and allows for creative traps (mini-nuke + frag mine = awesome)
-Much more realistic vehicle destruction system (no more nuclear cars that can be set off with a few shots)
-Support for ALL the DLC's.
-A tweaked movement system (you move faster)
-Bullet Casings stay for much longer.
-New bullet casing models thanks to "odin_ml" and his Shells and Slugs modder resource.
-The ability to bludgeon people over with blunt weapons.
-The dull green-brown sky replaced with a more blue-white colored one.
-New and more realistic ammo types: .22 and .50 caliber ammunition added.
-Vendors can now sell the new ammo types.
-Various inconsistencies fixed (Nuka-Cola Plant changed to Coca-Cola Plant, etc), no fanboy complaints, please.
-New menu backgrounds (more interesting, in my opinion).
-Level cap raised to 40 (may be removed if it causes anyone trouble, still waiting for peoples thoughts on that).
-A new gibbing system (high-powered weapons can tear foes apart or knock em down if they survive).
-New weapons such as a 40mm grenade launcher.