I can only interpret the "You" on Reverse Magic as referring to the controller, which is the enemy mage. So I'm not sure why you think the Cloak of Shadows blocks the reversed spell in this scenario.
Let's go over the possibilities for Reverse Magic :
1- Dark Mage w Cloak of Shadows plays enchantment/incantation from
0/1 zone away targeting enemy mage w Reverse Magic :
In this case, the Cloak has no effect and RM works as intended.
2- Dark Mage w Cloak of Shadows plays enchantment/incantation from
2 zones away targeting enemy mage w Reverse Magic :
The way I interpret the rulings, if the enemy mage pays the reveal cost of the RM, the enchantment spell will end up going to the discard pile as the enemy mage cannot target the Dark Mage due to the Cloak/Obscured.
( I also assume he cannot target another creature - there's nothing in the ruling that suggests something like changing the target in this case. )
3- Dark Mage w Cloak of Shadows plays enchantment/incantation from
0/1 zone away targeting enemy
non-mage creature w Reverse Magic and enemy mage is 0/1 zone away :
Again, a situation where the Cloak has no effect and RM works as planned.
4- Dark Mage w Cloak of Shadows plays enchantment/incantation from
0/1 zone away targeting enemy
non-mage creature w Reverse Magic and enemy mage is
2 zones away :
Here it gets fishy. Is the distance from the Reverse Magic to the Dark Mage the deciding factor ( 0/1 zone, in which case the Cloak has no effect ) or is the distance from the enemy mage ( 2 zones ) the deciding factor ( in which case the Cloak Obscures the Dark Mage and the RM would fizzle when revealed and paid for )
5- Dark Mage w Cloak of Shadows plays enchantment/incantation from
2 zones away targeting enemy
non-mage creature w Reverse Magic and enemy mage is
0/1 zone away :
Essentially same issue as ex4. Is the range to the RM or the enemy mage the deciding factor ?
6- Dark Mage w Cloak of Shadows plays enchantment/incantation from
2 zones away targeting enemy
non-mage creature w Reverse Magic and enemy mage is
2 zones away :
This case should be simple imo. Since the Dark Mage is 2 zones away from both, the RM and the enemy mage, the enchantment/incantation that was originally cast should never be able to target the Dark Mage.