The number of times I've freaked out over a PC dying in the heat of battle only to remember that it's a displacement clone is more than once. Could it be possible to give them a little effect to make it clear to people that your clone's just a clone?
I think the whole thought and intention behind modified mechanics of displacement spell is that it conceals what is copy and what is real pc.
Of course there are ways to determine who is who during the pvp, but there's still good chance that the copy dies/is going to be attacked first.
The copies do not replicate any skin effect you have on the original, such as blur, bark, etc., so it's fairly likely that anyone at a glance in pvp is going to work out who the original is. This would mostly be a quality of life change for PvE situations.