You know every time a new Halo is released we always wonder whats going to be new involved for us. I like paying more attention not just the multiplayer, but the forging too. I always hoped they would give us better vehicles to use instead of the same old ones, for example Pelicans, most of us want to see actual pelicans that can not only be used in campaign but in multiplayer/forge too. They could also bring back the old transport warthog from Halo 3, but better and improved.
Either way these are my opinions that could make Forging on Halo 5 and custom maps a whole lot more fun and enjoyable.