I actually use that trick to flatten and outline PDFs when required, but unfortunately that does pretty much the same thing as exporting from Indesign. It will flatten transparency too, so images are cut into bits and blocks.
All I need are the fonts outlined, but all images to remain untouched.
I think you already know this is not going to work. Unless one of the brilliant minds over in InDesign Scripting can come up with something, the only way to get outlined text out of InDesign that preserves ornamentation and bullets and numbering is to flatten transparency, and that is going to give you stitching on screen and in low res prints.
There are other disadvantages to outlined text as well -- can't be edited or searched in the PDF, nor read by screen readers used for acessibility.
I have never tried this - and don't have a working example to use.
But just thinking - if you could put the text on another layer.
Then export just the text to a PDF with layers
Then export the other side of things to another PDF with layers.
Is it then possible to move the layers between Acrobat documents???
Hmmm If I have a bit of time later I might try some things
I don't know if this help or not:
1- Put text on it's own layer
2- Put images on anthor layer
3- Hide the images layer, and use this technic:
Converting Text to Outlines The Right Way
4- Show the Image layer and hide the text layer, use this script to import the outline text: Placing All the Pages of a PDF Inside InDesign
At last export the layout to PDF