To the original question... yes please. As much character customisation as possible please. This is Games Workshop so much resource to tap into.
I could see people running around with armor that's roughly 10,000 years old. I think it would be cool if it actually showed the age from that time period. Nothing that looks deteriorating, just well used.
It's not "from the Horus Heresy". IIRC MK IV and VI are still produced on some level, they're exactly rare at all and can be found on both Chaos Space Marines and loyalists, despite the ten millennia passing. Also, the older marks of armor had better be able to be earned in-game as well as being in the cash shop. But the cash shop is excessive as is, we don't need to add anything more to a store for a game that hasn't even been made. Not that surprising. There's two MK IV helmets in the Warp Talons/Raptors CSM kit.
