Somehow the openess of graphic formats does not make Gimp a better proposition than Photoshop, specially when handling color workflows on digital agencies.

An image format mostly stores the end result of what you made.

An office document format is basically source code.

That's why the openness of a graphic format doesn't matter, but clear specifications on how to interpret an office document make an enormous difference.

Somehow you missed the point that openness of graphic formats has not helped to make Gimp better than Photoshop, likewise even if Office formats were 100% open, Libre Office features wouldn't match Word.

I didn't miss the point. I'm arguing that the two kinds of format are completely different. A graphics format is a side-effect of the actual editing, an afterthought. With an office document, the format itself is the core of the experience.

No, but it would allow LibreOffice to work with them cleanly which was the criticism I replied to (and probably allow Word to break itself less often or have 3-4 fewer implementations embedded in itself).