The primary difficulties with the directive are that it still requires prosecutorial judgment regarding the types of activities that will trigger criminal liability, so there is room for prosecutions based on conduct, such as sex with a condom, depending on the vague sense of other risk factors that aren't defined in the directive. That leaves the directive unclear and it is inconsistent with the community consensus statement that says where a condom has been used, there shouldn't be criminal liability.
It also still contemplates the use of sexual assault offences, again based on the exercise of prosecutorial judgment, based on factors that aren't clear. Given that the community consensus is against sexual assault offences being used for simple HIV non-disclosure, those are certain defects with the directive as it currently stands. Of course, the basic point that a directive is less clear than amendments to the Criminal Code, because it's just guidance for prosecutors, is a more long-term concern. If we could have the directive or a better version of the directive applied on the national scale that would be an improvement. But, ultimately, legislative reform is the only way to ensure clarity and consistency in the application to the criminal law.