Is the CJEU engaging in 'Judicial Abstinence'? Or, where do we go from here?

The CJEU has released the ebook of the May 2013 conference that celebrated 50 years of its Van Gend en Loos Judgment. The book contains many interesting contributions and, in my view, one of the most thought-provoking is Prof Catherine Barnard's 'Van Gend en Loos to(t) the future'.
Prof Barnard reflects about the future role of the CJEU in a changed and changing EU and identifies a trend of 'Judicial Abstinence' that 'leaves the uncomfortable impression that the Court is reneging on its key function, first articulated in Van Gend en Loos, that EU law must be effective' (p. 122).
Her analysis is relevant and expands well beyond the area of labour law, where she focusses. In my view, recent Judgments in other (even more fundamental?) areas such as the legal position and effectiveness of the Charter of Fundamental Rights of the EU also show the judicial abstinence the CJEU is (selectively) engaging in (for instance, in case C-313/12). And that leaves us with the difficult question of why is the CJEU (suddenly) so averse to (continuying to) act as constitutional court at EU level?
Pessimists could say that we are witnessing a deflation of the EU law supremacy balloon, and that the 'golden age' of the CJEU lasted 50 years and is already over. However, Prof Barnard offers a positive outlook as long as the CJEU departs from 'hardcore' judicial abstinence and opts for a medium-ground strategy (which she terms 'Old-Rules Lite'). As she stresses,
The EU of 2013 is infinitely more complex and any solutions will have to reflect that. There will be no Van Gend en Loos II. However, this does not mean the end of the Court of Justice and its influence. Quite the contrary. It means a repositioning of the Court from standard bearer of EU integration to ensuring that the EU is able to function in its new, more fragmented reality. This paves the way for the Court to develop a new kind of doctrine of effectiveness, one that might mean endorsing the devolution of more decision-making power to the Member States or other actors (p. 122, emphasis added).
The next few years will show if the CJEU is up to the task.