While I know there is a lot of work to be done on long-time feature requests, core improvements, and the like, it seems to me all the features in the world aren't going to be as useful without greater adoption. I don't know the real numbers, but my overall sense is that Tiki is less popular than I think it *could* be, and I think this is due in part to the difficulty in migrating from existing solutions. When people first start, MediaWiki is often the most obvious solution, whether due to its high visibility (i.e. as part of Wikipedia's visibility), or its relative simplicity, etc. But I think the general trajectory for many Wiki users is to start simply then realize there is a lot of missing or clumsily/awkwardly handled stuff in MediaWiki (and other wikis) and then have a desire to migrate. Making that process as easy as possible will surely be good for adoption.
The current spec for the XML format is here: https://www.mediawiki.org/xml/export-0.10.xsd
I don't remember for sure but I think the last supported format in the Tiki importer is 0.6 (maybe 0.4?). If that's the case it does not look like the changes since then are massive. Certainly it would take time to implement support in the import parser to handle the additional tags, but if they don't map to anything in Tiki they can just be ignored, and since they were never supported previously, it seems like that would not be much of a loss. In other words my sense is that supporting the updates to the format should not be tremendously labor intensive. Again I don't mean to trivialize the work involved, but from a cost-benefit perspective it seems like a good target for some development time in the relatively near future.
Of course I'm biased. ;-)
Is there a particular place where we can meaningfully promote/advocate for this, other than the forums? The lack of much official engagement here is a bit disappointing.