I think I prefer the option suggested by JV, i.e. have a configuration option at the level of the wiki to decide what syntax a wiki is using. Imports are required too but since WikiModel supports several syntaxes why not offer this feature to users. That would help a lot for people who come from an existing wiki and want to switch to xwiki.
The wiki pages importer will need to know from which syntax he is importing, so we still have 2 choices : 1) Have the syntax set at the wiki level and exported at the XAR level (package.xml) 2) Have a default syntax set at the wiki level and a mandatory meta in the documents (set at the creation, not assignable from the interface) : - we could write a new edit panel which would appear in the case were currentDocument is not using the default syntax, this panel would allow to switch the document to the current syntax. - it allows to change the default syntax (wiki level) without an automatic wiki-wide syntax transformation. WDYT ?