I don't think so and I have no idea what you're talking about. Skipping game content?
Insta-kill can be rebalanced. Insta-kill could reveal you to the rest of the world.
Stealth is by far the most hated skill in the game, as it does not seem to be useful enough. Doubling your damage with stealth does nothing as the second you attack, you're revealed to the whole world, often leaving you alone to face many enemies while your teammates are far away. Lone enemies are hard to find.
Placing mines around for 5 mins is stupid when you can simply run up there and kill everyone. Only a few hardcores actually use stealth in that way (myself included).
I want stealth to become mainstream though, so that everyone can consider it a good skill to invest your points into.
It's not like I want to have an insta-kill for final bosses. Important plot battles should still remain no-stealth duels/fight.