I've only been following the EU-ACP negotiations from a distance, and there were a number of aspects that I found confusing. For example, how serious was the talk about an end of year deadline? A good FT article from today offers thoughts and insights on a lot of the issues, including this one:
But since there is a dearth of case law, no one knows what degree of liberalisation would survive legal challenge. Some regard the EU’s insistence on the end-year deadline rather than, say, extending existing privileges for a temporary period, as aggressive and unjustified brinkmanship. The WTO disputes process takes years, so the spectre of the current agreements being mown down in a hail of hostile litigation on January 1 is unlikely.