We need this "new" mechanic to be implemented as a class-wide feature, in the same way that dodge is available to all classes. We need this because 6 years of powercreep has taken away all skill from the game¿ The better solution is to simply nerf everything rather than constantly introduce arbitrary mechanics (marked debuff causing reveal) but we all know that's not going to happen.
Ridiculous scenarios such as the following are why exhaustion needs to become a mechanic:
-Full Berserker Stats Thief
-Pistol whip (spammable evasion)
-Sigil of Energy (restore 50% endurance on weapon swap)
-Ãdventurer runes (restore 50% endurance when healing)
-Endurance Thief (restore 25% endurance when stealing)
-Sleight of Hand (reduces recharge on steal)
-Lead Attacks (reduces recharge on steal)
-Instant Reflexes (passive evade at 50% health)
-Hard to Catch (restores 100% endurance when CC'd)
-Feline Grace and Endless Stamina (permanent endurance recovery boost)
-Brawlers Tenacity (restore 10% endurance when using physical skill)
-Dagger Storm (evade)
And then there's pretty much any combination of utilities and weapon swap to amplify things even more. I can comfortably say that I've never lost to a skilled thief since HoT or PoF - every iteration of the thief has been broken in some way or another since launch. Other classes have this problem as well, although to a lesser degree. An example of another ridiculous build is the evasion spam condition ranger with troll unguent that you will never catch or kill.
How to implement exhaustion:
Each skill that grants evasion also inflicts an amount of exhaustion to endurance recovery .
100% is maximum exhaustion AKA no endurance recovery.
Very few abilities should inflict 100% exhaustion. Abilities such as elusive mind or hard to catch are such abilities. Examples:
And this in turn allows arenanet to change some skill functionality:
There is zero counterplay to evasion spam currently. Not even weakness because... you cannot hit them in the first place! And nowadays evading an attack removes the weakness anyway. The counter to evasion spam is that it needs to counter itself.