So why can Mirage have 2 abilities that turn him completly invisble

[SecretSwords]

While poor wraith leaves a trail a mile long yet becomes invisble at that point u might as well just add a cool ghostly effect to her instead of a bland * purple line running around

[Jedasilva]

You're definitely not seeing Mirages abilities correctly..

His Q send his dupe/to bamboozle (no stealth) and his Z pops out 6 copies of himself and you're not invisible - you're still able to be seen... 

I've had multi of matches where in the midst of mayhem I've been caught/seen while I pop'd my Z...

[JoeTheSho]

Mirage's ultimate is more of a transparent outline of himself, it's definitely difficult to spot at times but he's not invisible

[SecretSwords]

His passive he turns invisble and drops a decoy and as for his ulti it says right here he becomes invisble

Vanishing Act

Deploy a team of Decoys to distract enemies while you cloak

-Once Vanishing Act is activated, you are stealth for about 2-3 seconds

My point being why does wraith have to deal with leaving a trail while he can just poof out of existance

[Jedasilva]

There's still a clearly visible outlining on Mirage's Ult.

His passive pops him in stealth while he's down.

Why are you arguing abilities? Play Mirage for yourself and see how his abilities are and how they work.

Wraith is strong in her own ways and explains why shes massively played among so many different players.

Her Q is strong and can be used as an escape/reposition utility.

Her Z is overly powered as an escape, mechanic to save members of her team while they're down.

I personally think you need to step back and revise the mechanics of each legend... You're clearly missing the beat.