I have a big red bar when I login but I have not changed my password because it is complex and unique to Guild Wars 2 as are all of my passwords on all sites I use. The only way my password is a problem is if Anet itself has been compromised.
A more reasonable policy would be for you to check to see if I am using a blacklisted password and force me to change it if I am. It is not reasonable to force me to change a password because I MIGHT be using one.