While I find it’s a interesting mechanic on paper, it becomes a nightmare to deal with, because in a fight, it should allow the Wraith to be sneaky and choose an unexpected angle of attack, or better target. In practice, it’s spammed while you’re trying to chase it, forcing you to slow down with no repercussions or downsides for the Wraith, or in a fight, is spammed unless the Wraith is completely confident they can win.
It’s not necessarily the ability, but it’s the playstyle that the ability encourages, and ends up rewarding in some ways. A damage threshold on the decoy could help this, or maybe something that gives more of a fifty fifty deal to it. The decoy will run in a separate path or attack a separate target, but doesn’t flash when shot. In combination with the damage threshold it could create situations where a good wraith player would have the team thinking the clone was the real one, allowing it to do a sneaky attack on a Medic.
It also would allow more counterplay, allowing teams to do a 2 and 2 split, and not feeling like it just negated the whole team, only whichever group went the other way. As is, the current decoy just isn’t fun, you don’t interact with the real wraith, and it does a punishing amount of damage at no risk to the Wraith.