The Soulgrinder (very demonic/mutated Defiler) is a must needed addition to the Demon World army list - it's their main heavy support in the W40k list but oddly lacking in the current epic list (it's good they have access to the demon engines, but they really should have the basic choice too!). Close second would be Grey Knights Land Raider Reedemers and Razorbacks, since we have cool new FW models for those now.
I suspect in time all these will be added in time though, as for a new unit I will probably have to make up I would like to add a Giant/Greater Chaos Spawn for the chaos lists and make it AV or possibly LV (W40k have normal sized ones while FW produce a couple of massive spawn models). There are a couple of Warmaster chaos spawn models that could be perfect to use for them, and it gives players creative modelling opportunities to model something really big and chaotically mutated
I noticed slightly too late this was specifically in the Space Marine sub-forum, rather than asking about EpicA generally - oopsie! Probably Space Marine Veterans / Sternguard (or whatever they're calling them now) in that case.
