It'll hurt a bit if these powers can only be attained during a rare event. Apart from Crossbones this may include boss versions of Iron Man/War Machine/Falcon/Bucky/Scarlet Witch/Widow/etc., whichever Civil War bosses don't already have Skrull/Holo/clone counterparts.
...Come to think of it, if making Civil War content permanent is off the table then could the bosses could be moved to Holo-Sim and/or Danger Room afterwards? Seems like a lore-friendly way to take advantage of existing code.