snow is the best i have soooooooooooooo many ideas that involve a snow feel to it like one an invasion map that humans have dmrs and snipers and must silently infiltrate a covenant base in the middle of a blizard in the middle of nowhere. but still snow would be great like to see if one of the pieces is having those sticks of ice that hang from the ceiling.and forgive me if my spelling is incorecte i'm not a good speller
A Covenant-themed Forge with completely different, Covenant-style pieces with a more alien-feel. Maybe a massive hangar within the supercarrier Long Night of Solace?
^This. It would be so awesome and overwhelming, Making your own mountain ranges, making a flowing river through your map, the possibilities are endless.
I would have to agree with a couple people above, and either choose snow or covenant. Also, a new forge world would HAVE to have more variety in colour, rather than just gray. Possibly even the ability to change the colour of all pieces, and not just some of them like the current forge world.
A forgeworld with UNSC and Covenant parts would work really nice. Great for invasion and (in the case of UNSC crap) infection.
It would be nice to have a terrain editor like we could grab a piece of ground and "pull" it up or down to make our own terrain and if I had to go with one there it would be snow ... But a river would be cool too