I see what you mean (your upcoming customs sounds really cool by the way). Have you looked at this month's customizing challenge? It might be cool for you to make a Clone Wars diorama, with what you are suggesting.
I think that the difference is that the Group Projects, by nature, have always been a lot more strict. Usually there is one character that everyone is trying to make, there is reference material, etc. And the whole point behind it is getting people to make something they wouldn't otherwise try to make (like the Tonnika sisters, or the Mon Calamari dancer).
What you are referring to sounds more like the monthly customizing challenge, where there is a lot of freedom on what we make. For instance, one month it's smugglers, the next female hotties, the next Rebel troopers, etc. Allows for a ton of leeway.
Of course we make rules to try and keep things somewhat structured, but it doesn't mean you can't make something you want to. It's just our attempt at working on something as a "group" and seeing how we came about making the same type of figure. Which is why I hope more people try and make the Snow Bunny Padme so we can compare results and techniques.
This month has definitely opened up a lot though.