"[it] decreases the attention for methodology, for theory building, and for keeping enough professional distance to one’s object of research. This threatens to result in a creeping process of herd behaviour, in copy pasting the methodology of judicial lawmaking to legal scholarship and in a lack of transparency and methodological justification in scholarly legal publications".
Indeed, the part of their paper that I find really interesting (and brave) is the discussion on the risk of herd behaviour in legal research, where they warn about the risks of uncritically focussing legal research on 'hot topics' and the items in the agenda of policymakers/regulators (such as the European Commission) or financing/sponsoring bodies, instead of pursuing an independent ranking of relevant topics with intrinsic research/doctrinal value (pp. 305-307)--and which I remain convinced definitely supports their argument in favour of raising the methodological awareness in European doctrinal legal research.
In short, they submit that "the best response to growing heterogeneity of legal sources should be matched with a strengthening of theoretical and methodological components, where possible drawn from the common European heritage in legal theory and spurred by transnational scholarly legal communities" (p. 312). Moreover, they formulate some broad implications of their proposal and launch some open questions, which they intend to focus future debates about (the specifics of legal methods), particularly in view of the Europeanisation of legal education (see some related comments here).
Personally, I find the interaction between law and economics particularly important and I have some specific views as to what sort of methodology should be used in the study of European economic law [see A Sánchez Graells, "A Short Note on Methodology: An Eclectic and Heuristic Multi-Disciplinary and Functional Approach to EU Law" (2011)]. Ultimately, I praise and share the words of O Wendell Holmes in "The Path of the Law" (1897) 10 Harvard Law Review 457:
"I look forward to a time when the part played by history in the explanation of dogma shall be very small, and instead of ingenious research we shall spend our energy on a study of the ends sought to be attained and the reasons for desiring them. As a step toward that ideal it seems to me that every lawyer ought to seek an understanding of economics".
This is not to say that economics should drive, control or even dictate the objectives of legal research, nor that efficiency must necessarily be accepted as the ultimate normative value. However, legal research that disregards economic theory and its insights and (willingly or inadvertently) runs against them will have a very limited (if any) value. Moreover, the same is equally applicable to other social sciences and, as van Gestel & Micklitz stress
"this should not imply that we want to turn law students [or law scholars, for that matter] into amateur social or political scientists or economists, but they should at least be able to understand (some of) the language and methods that other (social) sciences apply in order to learn more about the value, validity and reliability of non-doctrinal research methods and techniques" (p. 315).