Currently the password generator limits the length to 50 characters, and the maximum number of combined letters and symbols to 10 each. These are artificial restrictions which reduce the entropy of the generated password, and should be removed.
I should be able to generate passwords that are 100, 200, or -- for kicks and giggles -- 10,000 characters long if I want to. 50 characters is not a enough.
The number of digits and symbols should be chosen randomly, and should not be limited.
If an attacker knows that a target uses 1Password, and can assume that they generate the most secure password possible giving these restrictions, then they now know that the password is 50 characters long, and that it contains 30 letters, 10 numbers and 10 symbols. This significantly reduces the time it would take to crack, and should be considered a security bug.
KeePass currently does a much better job of this, and 1Password could learn some lessons from it.