I don't think the problem with Sting is looking at opponent's hand. I think it's once again the problem you have mentioned - removing twilight.
this is absolutely incorrect. absolutely.
1) playing around ALL their cards with perfect information is too powerful (ie oh look they have a savagery, i won't play my 5th companion)
2) being able to perfectly count the twilight costs of their minions/plays and selectively choking is too powerful
3) being able to see what FP cards they have coming up makes your shadow deck better and is too powerful
getting perfect information for almost no cost every turn was why
sting was banned.
here's a replay elucidating this concept:
http://www.gempukku.com/gemp-lotr/game.html?replayId=mikefrench$7vvat3xeh15w6cjpin my turn 1 fellowship phase, i get
sting and use it before playing last alliance. i note that if i play last alliance he will be able to play
morgul gates + nazgul. so i prevent him from playing ANY cards by using
sting and managing twilight.
in my site 3 fellowship phase, i
sting and see that playing sam will not allow him to play a 2nd nazgul, so i can get away with dumping my entire hand.
in my site 4 fellowship phase, i
sting and see that i can prevent him from playing more than 1 nazgul by not playing my boromir and my orophin.
this enables me to dump my hand in my fellowship phase at site 5, knowing that my 3 elf allies will be able to help out in skirmishing his hand that has been choked full of nazgul.
so by careful use of
sting, i was able to survive the early onslaught of nazgul, when they are at their most dangerous. i was able to survive long enough to set up my fellowship so i could thrive at sites 7-9.