Well, there's your problem
No capital letters.
On second thoughts, I imagine the iterations over character classes goes lc, digits, uc, symbols, based on common usage patterns. So you can probably still get the complexity benefits for brute-force resistance of uppercase letters even if you don't actually include them, but still use symbols. The uc letters will be checked anyway, but more symbols puts the check of your password at the back of the list; brute forcing "aaaaaaaa" must be pretty fast, but ";;;;;;;;" slow.