"I think that many wikis want Forms to be something strict and provide some guarantees. Here the argument "it's a wiki" is not sufficient: some wikis prefer not to show the markup to the users at all."
Ya know it's impossible to edit annotated values too... is it thought to shut that down too?
Drupal may be a better fit for the site in question if there's a need for absolute control of page content or proprietary templates are involved. Otherwise, I suggest "gardening" to ensure stored values are within tolerances and attach messages to pages with bad values or red links, perhaps even dropping those values whenever the wiki's content is mission-critical.
I think there's little wrong, and ALOT right, about SF, particularly its embedded template functionality. If anything for validation, maybe regex formulas could be attached to a field...
Thanks - john