I am working on redesigning a fairly high profile blog. I suggested
the best way to do that, rather than mockups, is to just upload their
wordpress export to a new WP install on domain.
I periodically (twice a year or so) pull the database from our primary site and import into a dev site. Other than the couple of caveats with moving a site, it presents no problems. Images will not be moved with a db transfer though, but mostly that isn’t an issue. They load from the main site for the most part.
If I did this on my side with an export, it might take a week or so.
They client would then have to import the fixed export… right? Any
issues with that? What would happen to the content that was created in
the previous week? Would a next export have to be created and the
previous weeks content be joined to the older, fixed, export?
Unless you essentially freeze editing of the site for the duration this is going to be a nightmare. Even if you do freeze editing I’d consider it fairly dangerous. You are basically destroying the old database with the import. I would keep very, very good backups– several.
In fact, I’d import to a new database if you have the ability to do so. Then swap databases with a simple wp-config.php edit to change the database, and check for sanity. The old site/database is recoverable by reversing the wp-config.php edit.
Both options mean that edits on the live site between your export and their import are lost. Merging the databases is not something I would want to attempt.
If you must do this quickly, grab the database and work up a script that will reorganize the categories for you. Upload the script and run it, but you better make sure the script work correctly before you do.