Space Marines do always seem to have the most interesting discussions! It's a good thing they're not as rare in EA as they're supposed to be in the background
With all these ideas, why not create a new list that starts off exactly the same as the current one and then modify it? Ortron and Blip's (and many others'!) ideas about more modular Space Marine lists, or the ideas of sensible differences from the original, could be incorporated there. Just because there are specialist Space Marine lists doesn't mean that people couldn't work on a generalist list if they would like to—perhaps, to use the metaphor, one of the horses can be reigned in, even if all the others are now free with the Silver Brumby? The specialist lists would inevitably be better for their particular playstyle anyway, so the design philosophies are not completely overlapping, and the original Marine list remains safe.
One question is, "Why not just house rule it for your own games?" But (like with all the crazy new ideas we post on here
) here, you can get everyone contributing good ideas. There are lots of erudite EA sleuths, so why not make use of some of their expertise and maybe make something everyone can enjoy?
I suppose one issue with adoption of new Marine lists is the prestige of the original list: it will always have that veneer post-official support but having expert EA people here make comments on new lists gives them a lot more prestige, too.
An interesting discussion, nonetheless. Space Marines seem to embody some of the most iconic mechanisms of EA!
As an aside on activations, it would be nice if there was a strategic way to build activations into a list that didn't rely on the suspicious 'more units = more easy to control them' axiom... it seems such a shame that so many options are limited by that caveat! But this has been discussed elsewhere, and isn't really a Space Marine problem!