Our scenario: we have "portalowners", who don't belong to the Administrator role, but who have edit role for parts of their portals (on site and/or module level). For new pages and changes to settings we would like to use templates with the option MERGE to introduce those changes on all portals without loosing existing content.

My exact way of testing this:
1.) create a source portal PORTAL1 with modules A, B and pages 1,2,3
2.) create a template from that source portal (without content)
3.) use the template to create PORTAL2
4.) add modules + pages to PORTAL1
5.) create a second template (no content)
6.) use the site wizard in PORTAL2 with the second template and option MERGE

With the MERGE option neither pages nor modules were added and also no settings of existing modules and pages were changed.
So I'm wondering about the way MERGE - option is supposed to work?

I couldn't find any documentation on the mechanism for merging an existing portal (PORTAL2) with a new template!
Is the template going to override any setting in the existing portal? ...