I think I understood pretty well the Tarot stuff, but I don't get why I would do a Tarot in any other star system than Chernobog. Base XP is always the same, whatever the subsector, 75. The bonus, you can get via cards is always the same too (I actually run for 110 rank xp), and I don't see Tarot as a way to up the account level (there are enought missions to get account xp, not talking about AccRush via high players), so why would I, right now, change the system to do a Tarot in a harder difficulty, if everything is the same whatever the sector.
Maybe you could rethink Tarot about that, let say, by the quality of loot, or changing the rewards rate, to for example, 5 craft items if it's in Chernobog system, but 20 in the Lacaon. To give to players motivation to do Tarot missions in other subsectors than where they get +200%dmg/-95% received dmg. Oh, be sure it's pretty satisfying to kill em all on very easy difficulty, but still, in the end.. something is missing.