Hi Markus,
here is the problem with a ReDJ import/export feature, and why I've not implemented yet.
A ReDJ rule is a regular expression that can match more than a single URLs. So, ReDJ is not properly a one-by-one tool like Joomla 1.7 embedded Redirect. So a function to import Google errors is not so useful until I will not implement a special kind of rule, let me say, an exact match redirect, where I have a full old url and a full new url.
Meanwhile, for these cases I suggest to use Joomla Redirect. Users can prepare a list of old -> new url (e.g. excel sheet) and I can help to import into Redirect.
I hope this makes sense for you.
Best regards,
Luigi