Personally I believe we can work on making the requirements better, but without removing big blockers.

If themes are moving towards being style guides for new content blocks, I don't see why TRT should start encouraging content creation.

I also don't believe that the "Use WordPress functionality if available" and the content creation requirements should hinder designers. If authors can't work within the guidelines, perhaps it is they who lack imagination.

Should new features first be tested in the theme directory?
Is that the best way to recieve backing for your new ideas?
I would suggest participating in meetings, developing feature plugins and opening a trac ticket etc.