I suppose some of this has been brought up before but I have been considering something for a while and I wonder if there is any legitimacy to it.

I am thinking that the appeal of the armies has something to do with their relationship to the armies of the Imperium. It is well established that the Imperium of Man is the core storyline of the WH40K universe, and what I got to thinking is that armies such as Space Marines and Witch Hunters tend to symbolically embody "faith" as their primary theme.

A number of other armies represent things that are sometimes seen as challenges to faith today - heresy for Chaos, secular ideas for Tau, evolution for tyranids - and perhaps the lasting appeal to all these is their symbolic opposition to the Imperium. It may be that this is true for some, or perhaps true for every army (I can't think of what they all represent offhand), or I could be reading way too much into it, but it can be said of anything with lasting appeal that symbolism is an essential element.

Anyone else have similar (or totally different) ideas?