Just as no consensus has been reached about all the proper roles of a company, we have no final conclusion on the proper role of a law department.
Roles expected of corporations include to maximize profit (law departments are expected to minimize costs), increase market share (law departments should serve more internal clients and handle more work in-house), improve the community (legal departments undertake pro bono projects), promote diversity (ditto for law departments), conserve the environment (ditto), encourage personal growth (ditto), optimize productivity (ditto), and increase the quality of goods and services produced (ditto).
Roles expected of corporations conflict with each other and change over time. Ideology underlies everyone’s conception of those roles of both corporations and the law departments that serve them. The people who respond to those demands have different personalities and drives, and all of the mix changes over time. Likewise with law departments. The scope and depth of any law department remains malleable, with no chance that they will be set for long periods (See my post of Sept. 3, 2008: survey of the responsibilities of the general counsel.).