From https://gerrit.wikimedia.org/r/#/c/266758/:

Adrian Lang Jan 30 9:12 PM

I would probably opt for reworking the way formatters are passed to the ValueView. Currently, that's done via a FormatterFactory with quite a complicated interface. Instead, I would just pass a formatter { format: function( dataValue, mimeType ) -> $.Deferred }. Passing PropertyIds and DataTypeIds would then be done by the snakview. If we do the same for parsers and experts, we can remove the dataTypeId parameter, which indeed is wrong.