If I play Blessing of Isha on my opponent's skaven, does that prevent them from corrupting to use their Actions? Thr former does not appear to have a target restriction...
Blessing of Isha
Attachment. Spell. Attach to a target unit. Restore that unit, if able.
Attached unit cannot be corrupted.
Poison Wind Globadiers
Θ HP 2 Skaven. Destruction only.
Battlefield. Action: Corrupt this unit to deal 1 damage to one target attacking or defending unit.
Correct, Action isn't triggered as the cost isn't & can't be paid. Even more effective with Deathmaster 
You can use Skaven in "destruction only" deck (Chaos, Orcs and Dark Ellves)... not in a High Elves deck or any other Order Deck (Dwarves and Empire)
lucarov said:
You can use Skaven in "destruction only" deck (Chaos, Orcs and Dark Ellves)... not in a High Elves deck or any other Order Deck (Dwarves and Empire)
OP states he is playing Blessing of Isha on an opponent's Skaven, so this is not an issue.
I pointed this out immediately following the Warp Cannon ruling. Isha becomes a way to prevent the Skaven from corrupting itself as part of the cost to trigger its ability.