Phantasm illusions look exactly like e.g. Manta Style or Illu Rune illusions, despite being like 10 times more powerful than them.

Also, having them all the same color is not user friendly in general. Units with different traits should look differently. Chaos Knight's illusions are not the same as Manta illusions, so they shouldn't look alike.

Note: The color would still be allied-only. This would make no difference for enemies, since they see the illusions like the original hero. This would only be a QoL change for the player and their allies.

Here is an example of a red illusion, compared to the default blue illusion and to the original hero.

(I did not use a proper skin here, this is just a color change to 255|0|0. A proper red skin would look way better than this demo here)