With the OpenBeta release two years ago we also got a new missile flame exhaust, it looks fantastic no question. But this new effect doesn't match the flame exhausts of other different missile types.
For example the AMRAAM's have a completely different looking flame exhaust as compared to some russian build missiles or the Sparrow missile and more.
I'm not an expert but I believe there are different flame exhausts due to different rocket motors? Or does it depend on factors such as weather or alltitude, maybe both or all together?
Here are two examples to display the differences quickly.
I haven't really thought about it but I would really like to see the missile exhausts varying from each other in DCS World.
There aren't much reasons to spend the needed time and recourses towards differences in the missiles flame exhaust but I think it would fit the eyes much better.