Since Dries mentioned it in his post, I figured it was OK to open an issue for this.
The Panopoly distribution is the best example of WYSIWYG content layout that I've seen so far in the Drupalshere. Not only is it already impressive (and getting better quickly), my impression is that the architecture provides most of the elements for taking it to the next level. There's a lot of stuff to like in Panopoly, as well as some remaining shortcomings.
While I was happy with the recent revisions to the Panels "edit-in-place" interface, the feature that made me say "Wow" in Panopoly was the previews it provides for content *as it is being added* to the panes... nice.
I only recently discovered Panelizer, but I love it! It allows you to enable 1->n layouts/templates on a per bundle basis and allows these to be overridden on a per-node basis. Moreover, you can lock regions and get pretty darned granular in the control over who can change or add what. Again, it allows you to pick from existing styles or define new, reusable ones, then provides the drag-n-drop and edit-in-place, etc.
I was also surprised and impressed that it incorporates Display Suite as well, but have to admit that I'm still keeping that at arms length for the moment.
The "Stylizer" functionality in Panels is very limited and unsatisfying at the moment, but to me it shows a lot of promise for providing workflows that balance creativity and structure, i.e. where you could have WYSIWYG-style-editing, but on a per-component basis (field, pane, region, page), again by creating/re-using styles... all the while respecting access control, etc.
Simply augmenting the Stylizer to allow the addition of background images and other CSS elements, putting the "*preview* in place" with the Stylizer options in a pop-up and you're already reproducing the pattern of most graphic design software.
Unfortunately, the suite still falls a little short in terms of cohesiveness (so far). I mean, "panels everywhere" is available to help you take control of the whole page, the Panelizer piece gets you control over the main content area, the mini-panels are for complex layouts of sub-elements and the Display Suite integration to act at the field level. They all provide drag-n-drop, but they are not compatible. So you have multiple (overlapping/redundant?) places to enable/manage the use of Panels (e.g. Panelizer page, the Page Manager, the Panels Overview page and Mini-Panels settings pages) and you generally can't drag from one into another (e.g. a pane from a "mini-panel" into a "page"). But even if you could, you'd need some fancy and yet simple means to confirm/modify the contexts, arguments and such along the way.
So, again, the Panopoly distro is the best I've seen so far, but still have a ways to go.