So what could be a simple, optional, no-buy-in solution? How about a
minimal breadcrumb trail: a link to the top of the wiki plus one to
the parent page -> being the page on which the current page was first
named. This info is used to populate the initial text
(currently "Enter some content for your page") of the new page with
((home)) | (([currentpage])) and maybe a horizontal rule beneath it.
Users who don't want the links simply delete them as they do the
current dummy content.
I just finished implementing this feature, and it's now deployed on the site. You can try it out by creating a new page on any of your wikis. As Richard suggested, it creates a breadcrumb bar with links to the project home and to the previous page, and this breadcrumb bar can be deleted at any time if it's not wanted.
Richard and everyone else, let me know if you want any changes to this default, either in content or styling.
A bit longer-term, I'd really like to make this feature configurable by the project administrator, so you could build your own "blank page template" if there's any particular layout or content you use on all of your pages. That probably won't happen until I've moved everything over to the new wiki system (the one that currently powers the "Extra Wikis" feature)