I will look into this once there is a realistic test site. QS2 is designed for multiple sites, see https://phabricator.wikimedia.org/source/tool-quickstatements/browse/master/public_html/sites.json
FYI, @ChristianKl commented on QuickStatements2 functionality at https://commons.wikimedia.org/wiki/Commons_talk:Structured_data/Get_involved/Tools:
"One of the big problems with QuickStatements is that it's an external tool. Given that banning a user that has an active QuickStatement batch running doesn't stop the batch, there talk on the Wikidata Admin chat that we sometimes might to temporarily block the QuickStatementBot. Undoing QuickStatement batches is also generally cumbersome. I think it would be very valuable if the functionality would be integrated more natively. If Wikidata (or Commons for that matter) would have a representation of all the edits that come from a batch as a batch it could provide an easy way to undo/redo the batch or discuss it. ChristianKl (talk) 11:05, 26 November 2017 (UTC)"
And FYI2, this partly corresponds with two of the user stories that @Ramsey-WMF has outlined for Structured Commons:
An addition to these user stories would thus be, that batches must be easily undo/redo/discussable, so that Commons admins also don't hate their lives.
One sidelight on this. QS2 is great (invaluable!) for adding new statements, but not so good for modifying existing statements, especially if they are currently heavily qualified or referenced -- at the moment, the entire statement complete with all qualifiers and references has to be re-created, even if one only wants to change one qualifier value, or migrate the property being used for the qualifier.
Not sure what the answer is for this, but it may be a sharper issue for Structured Data, because there may be types of statements there (eg attributions?) that we will be expecting to quite heavily qualified, as part of the data model.
One other thing to note is that QS2 is currently throttled a lot slower than eg Cat-a-lot on Commons. If the Structured equivalent of Cat-a-lot were using QS2 as a back-end (not an unreasonable possibility), it will seem x10 or x50 more sluggish than the present Cat-a-lot.