There are a lot of markings and items in those packs, and it would be very difficult to get permission from each and every marking maker and item maker/converter to use in the game. Lots of the markings and items are very old, and odds are many of the creators may not be around FH anymore
Even if we did manage to get permission, there are just too many items and markings to put in. That number makes it way too difficult to scroll in those boxes in the character creator (and we can't expand those boxes due to not having the source code) and sometimes it's quite the hassle to find what one is looking for. Not only that but the amount of markings and items could be too much for some people's games to handle, especially the items (especially the car/tank items, items that are animated, etc)
Thank you for the idea nonetheless, and staff have considered ways to fix this problem