Chris,
That was tried to some extent, at least in the CWG.
There are several substantial problems with that approach.
First, lawyers are not fungible. The particular legal skills, background and experience required for the issues before both WGs are fairly specific, and in some cases, very specific. The primary core competency needed here is corporate governance. While a number of lawyers in the community have a reasonable working knowledge of the area, at least in their home jurisdictions, I don't believe there are any who would say that this is their primary focus and expertise -- at least none who identified themselves to either WG. The second core competency required, especially in the CCWG, is non-profit law. Again there are a number of lawyers with a decent working knowledge of this fairly broad field, but not as a primary focus. There may be a couple of lawyers in the community who would claim this fairly broad field as a primary focus and expertise -- but none who became involved with either WG. This then becomes further narrowed by jurisdiction. Since ICANN is a California non-profit corporation, US corporate governance and non-profit experience is more relevant than experience from other jurisdictions, and California law corporate governance and non-profit experience is more relevant than that from other US jurisdictions. In my experience, the more a US lawyer focuses on a particular substantive area, the greater their knowledge of and comfort with state law issues in US state jurisdictions other than their own (e.g., someone who spend a majority of their time working in corporate governance will have a greater knowledge of the law, issues, approaches and trends outside their primary state of practice, while someone who spends a relatively small amount of time in the area will tend to feel less comfortable outside their home jurisdiction). (An exception is that many US lawyers have specific knowledge of certain Delaware corporate law issues, because Delaware often serves as the state of incorporation for entities operating elsewhere.)
Second, lawyers in the community will seldom be seen as neutral advisors, no matter how hard they try. They will tend to be seen as working from their point of view or stakeholder group or "special interest" or desired outcome, even if they are trying to be even-handed. Over the course of time, this balancing act would tend to become more untenable.
Third, the amount of time it would take to provide truly definitive legal advice (research, careful drafting, discussions with relevant "clients", etc.) would be prohibitive, even compared to the substantial amount of time it takes to provide reasonably well-informed and competent legal-based viewpoints in the course of either WG's work.
Fourth, in order to formally counsel the community, the lawyer or lawyers in question would have to enter into a formal attorney-client relationship. Under US law, an attorney-client relationship may inadvertently be created by the attorney's actions, so attorneys try to be careful about not providing formal legal advice without a formal engagement (sometimes providing an explicit "caveat" if they feel they might be getting too close to providing legal advice). If the attorney is employed by a corporation, they would likely be unable to take on such a representation due to the terms of their employment, and that is before getting to an exploration of conflict of interest issues. If the attorney is employed by a firm, the firm would have to sign off on the representation, again dealing with potential conflict issues.
Fifth, even if the above issues were all somehow resolved, it would be highly unlikely that any such attorney would provide substantial amounts of advice, written memos, counseling, etc. on a pro bono (unpaid) basis, especially given the time-consuming nature of the work. Pro bono advice and representation is generally accorded to individuals and entities that could not otherwise be able to pay for it. That is clearly not the case here, at least with ICANN taking financial responsibility. It would likely be very difficult to justify this to, e.g., a firm's pro bono committee, as a valid pro bono representation.
Sixth, if ICANN were not taking the role they are taking, it would be extremely difficult to identify the "client" in this situation. The "community" is a collection of sectors, mostly represented by various ICANN-created structures, which in turn have members of widely varying types (individuals, corporations, sovereigns, non-profits, IGOs, partnerships, etc.). This would also make it extremely difficult to enter into a formal counseling relationship with the "community."
Seventh, this is a sensitive, high-profile, transformative set of actions we are involved in, which is subject to an extraordinary amount of scrutiny, not least that of the NTIA and the US Congress. That eliminates any possibility of providing informal, off-the-cuff, reasonably well-informed but not quite expert, "non-advice" advice -- which might happen in a more obscure exercise. There's simply too much at stake.
Finally, I would say that a number of attorneys involved in one or both of the WGs are in fact providing a significant amount of legal knowledge and experience to the WGs, helping to frame issues, whether in terms of general leadership (e.g., Thomas, Leon, Becky) or more specifically in a "lawyer-as-client" capacity -- working with outside counsel, tackling the more legalistic issues, providing as much legal background and knowledge as possible without providing the type of formal legal advice that would tend to create an attorney-client relationship, etc. So I do think that many lawyers in the community are giving greatly of themselves in this process, even though they cannot and would not be able to formally be engaged by the community as its "counsel of record."
In sum, it might be a nice thought in theory, but it is no way a practical possibility.
Greg