Maybe you able to add your dreams for current feature-request -> http://community.f-secure.com/t5/Feature-Requests/Easier-maintenance-of-passwords/idi-p/50321
And it some kind of have same points already. And some kind of "maybe it will be with F-Secure Key";
But for my opinion - here have just one "trouble"-design point:
For checking "duplicate" and "how strong" your password (security-level) need to have something "hard in logic" (which probably OK and good) or F-Secure should be know.... your password.
Last one not connected with F-Secure Key design:
"We don't need to know who you are. We just hope you like the product"
Also now F-Secure Key work with hash by password. And checking for "security" can be just about here have "numbers, capital characters, specific characters and minimal lenght" before creating master-password - it's not enough for good checking about security-level
Because "enough short password with specific characters, numbers and capital-characters" will be not really better, than "long password just with numbers" and other variants
For checking that -> need to check password - and without reason to check "hash". Probably it can be without any design-troubles, but... how it certainly can to help you... if current password will be without protection by service, where you use it
Probably F-Secure Key can just to give any tips (more good tips) for creating strong password.
But "random" feature about generate password in Key - also can be enough with all settings (and manual edit.. if some of specific characters not able to use with current service; or if here can be just limit of maximum characters).
But yes... all of that.. good potential features... which also can be "else more" and some of them... have on feature-request by link.