I've been thinking about it and the Halo warbond is actually such an obvious one
putting ODST drop pods, UNSC pelican, and four seater warthog as skins should be easy, interesting part would be to see if the warthog skin also gave us a genuine gatling with no annoying reloading
the scoped god pistol, battle rifle, and double barrel rocket launcher are shoe-ins for meta relevant primary, secondary, and support weapon
the throwable mini shield relay for a grenade, how about it
the ODST armors could just be allowed to be the much needed medium siege ready additions for free access to metaslave builds while dripgods get a functional perk on top
a goated addition would be the mongoose since we need a super light solo+duo vehicle but that might be too much hopium huffing
name the UNSC weaponry (You) want to see in HD2 anon