Yeah, I mained Mirage for a while - he's actually got the most stats of all my characters. But after being gunned down while in my "ult" and people ignoring my decoys, I started playing with every other character.
I understand that he can't be OP, so leave the Tactical alone. The decoys still work occasionally if they don't see you.
The Passive is pointless. I get "cloaked" but someone that wants to finish me right away will do it every time.
The "Ultimate" is the least effective of all the legends, I would say. The decoys don't do anything, so it's pretty easy for someone to focus on your 80% visible body and shoot you while you can't do anything. It's pretty frustrating and doesn't pay off.
I agree with everyone here. He's gotta get buffed before I use him again.