Honestly? I think the idea that everyone already knows it's a clone every time is a but overstated.

Gamers have a hard time not pulling the trigger and dropping a clone at a deathbox or supply crate while on the run has worked great for me to find out if anyone is following my squad.

Clones are great in firefights b/c they're generally so chaotic that even pros aren't going to immediately tell so you can bait them to look in another direction...and that's really what Mirage is best at, buying a few more moments.

As for his alt, a modest "rework" I would like to see is the ability to change the formation of the clones so I can occasionally use it offensively.

Essentially a mass version of his Tact that I can aim at a location and who all move a little randomly (balanced by not being manually controllable) to either hide within during a push or distract while I flank/retreat.