Well, you've always been ahead of that curve, BL.
I think Epic at it's best neither tries to ape 40k, nor ignores the changes going on in it's big brother. A stagnant community will evaporate, to be sure. However I think we need to be aware of model availability, list balance, and player pool size, too.
Take the new Necrons. The old Necrons were full of Lovecraftian horror and mystery - and I loved the background for that reason. The new Codex stripped all that away, and they lost their interest too me. I may still make a Necron army, but it will the old Necrons. I know some feel the same, and that means that the player pool for the new Necron lists is neccessarily limited. Without a broad player base, a list cannot be properly vetted. Another problem is model availability. There are proxies available for the old Necrons, but not for many of the new units - without widely available models, the new lists will see little action. Stand-ins are all well and good, but only in the short term.
Finally there is list balance. Lists in Epic are created from whole cloth. The interactions between units (combined arms) are as important as the units themselves. This differs from 40k where GW feels free to add units to old armies because the units are more important than combined arms. In fact the best armies in 40k are armies that spam certain units (leafblower Guard, for instance), whereas doing that in Epic usually weakens an army. Thus we usually add new units to new lists, instead of inserting them into old ones. The drawback is that there are only so many players, and only so many lists those players can support. We seem to be nearing a saturation point for lists in development, where adding more lists simply fragments the development instead of adding to it.
All this means new units are less likely to make it into Epic, though all these hurdles can be overcome. For those units that add something truly new to Epic, there will always be room. It may just take a bit to happen. For those that add nothing existing units do not, 6mm allows a great deal of flexibility to 'counts as'.
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SG
Ghost's Paint Blog, where everything goes that isn't something else.