Mirage is a bit of a problem child and in my opinion, its design is flawed. After numerous nerfs mirage has reached a point where it doesn't perform well anymore and doesn't play well either. This is the result of nerfing numbers but ignoring the core problem of the elite spec. In this thread, I will share my view on how to rework mirage. For the sake of ease, I will only talk about condi mirage.
First of all, let's identify the design problem of mirage: the dodge. It can be used when cc'd and it allows continuous pressure where other specs have to dodge skills and can't attack at the same time. How can we solve this? No, not by removing one dodge from mirage but by splitting the functionality of dodge and ambush. What's the core mechanic of mesmer? Exactly, clones and shatters, yet condi mirage rarely uses shatters...
Change #1: Mirage gets its second dodge back.
Change #2: Dodge does not apply mirage cloak anymore.
Change #3: Mirage gets access to a new F5 skill called Ambush. Ambush on weapons is removed (functionality remains the same). Ambush F5 can be used after using a shatter skill with 3 clones (maybe 2, hard to tell). This makes it possible to store one ambush instead of having to use it in a limited time frame after a dodge.
Change #4: Infinite Horizon (Mirage GM 1) is replaced by a new trait called Heat Fibrillation. Heat Fibrillation Applies 1 stack of burning for X seconds per shatter (max 3 clones + you = 4 stacks).
With these changes mirage will get 2 normal dodges again, making the player choose between defense and offense. Furthermore, mirage will be encouraged to use its shatter skills once again. Mirage cloak will remain in the game from certain skills (heal, etc), it just won't give you ambush skills anymore and the uptime will be much lower. With Infinite Horizon removed you will be challenged to keep your clones alive so you can get enough shatters to enable the new F5 Ambush. The new GM trait Heat Fibrillation makes up for the damage loss because shatter skills have overall longer cooldowns than a dodge, especially with double energy sigils. You don't just want to buff ambush skills for the lost damage, this would make the spec too one dimensional, instead, burn on shatter will reward you for hitting your shatters.