Default user page title token should use [user:display-name]

account-name is still the same internal username, my point is that it should use display-name, which is the "formatted" display name of the user. Otherwise modules like realname will not work correctly.

Not sure about update function. Maybe if you check if the old value was using the :name token like the default but not sure if it's really worth it. Existing sites can always update it manually.