SF NERF change into a crit strike based (5secs lastings)

So all the speculation about how to nerf SF brought me up on my own idea.
Remember the skill critical agility? It only lasts for 3 secs (with SS rank more) and renews when a critical strike is brought. How about make Shadowform only last for 1....3....5 seconds and it renews by making a critical strike if not, the same effect is caused as it is now.

Elite Enchantment Spell. For 5...18...21 seconds, all hostile Spells that target you fail and all attacks against you miss, but you deal 33% less damage. When Shadow Form ends, lose all but 5...41...50 Health.
10 EN
45sec Recharge
------------------------------ INTO --------------------------
Elite Enchantment Spell. For 1...3..5 seconds, all hostile Spells that target you fail and all attacks against you miss, but you deal 33% less damage. This skill renews each time you make a critical strike.
10 EN
45sec Recharge

To prevent being overstriked with a scythe make it dagger use only. Even with a scythe it would be hard to keep it up all times. Because you still got to walk to mobs to keep it up. This requires to make a player play with more a brain and skill.

Type /signed or notsigned please!
Give constructive comments please!

too much speculation for a horribly stupid idea that defeats the whole purpose of what the skill is meant to be.

anet's gonna do what anet's gonna do whenever in all the living hell they feel like it. END OF STORY.

Or how about we don't do anything stupid like "attacks and spells against you fail" and actually come up with a skill that's useful for something else than tanking and sc?

There's no need for any SF nerf threads until the actual nerf comes.

Thanks. Closed.