Guild Wars 2

Why in Spvp the duration of Save Yourselves (Guardian) buffs is 5 sec and the duration of the conditions of Spite (Necro) is of 10 seconds?
One is a single skill that give you a large amount of buffs (not all) and one give to your enemy a large amount of conditions (not all).
Save make you harder to kill, Spite make you harder to be killed by that enemy.
Save make you more good in fight, Spite make one enemy unable to fight.
Save is a single shot skill that need to be traited to clean a condition and that make you acquire all the party members conditions (that is a good and a bad thing at once), Spite give you 180 Power in Passive Ability.

Then why only one of that skills has been nerfed?

(P.s. sorry for my bad english)

1. save yourself is a stunbreaker.
2. save yourself has 7 boons, spite 6 conditions
3. All boons are very usefull to a guardian the same can not be said of the signet.
4. The power of signet of spite is kinda useless since it’s active is mostly used by conditionmancers.
5. signet of spite can be dodged/blocked/interupted/… if I’m not mistaken.
6. cleansing of conditions is easier then removal of boons.