Some sites are problematic and that pop-up prompt you get so used to clicking "Save". I've had problems with MS Exchange web access at work and today Blizzard Entertainment's Battle.net. Sites with 2-step verification often have 2 password fields. It copies the wrong password and then you overwrite the old one accidentally. If you use a good password generator, this leaves you without access. Feature request: A per entry "Never update" check box in addition to an entry specific check box for keeping a brief PW history for problematic sites. Could put in a warning that history is a last resort." Store the history in memory so that it goes away when the browser shuts down. A more secure alternative would be to have an additional button that updates the timestamp only rather than the userid / pw fields and a prompt if the current PW is different from the old one.
This review is for a previous version of the add-on (3.6).
... is that the more prompts you add, the more they are being ignored. So adding more prompts can make the problem worse; however a "recover last password" might be an interesting feature for your use case. I am also currently working on a backup / restore functionality, I am just missing the (difficult) encryption bit.
In the meantime - can you please raise your feature request at my support site: http://quickpasswords.mozdev.org/bugs.html
Update - related bug: https://www.mozdev.org/bugs/show_bug.cgi?id=26141
Update2 - I created a user account at battle.net, but cannot find the 2-step verification you mentioned. Their login page