Do we need special ethics rules for big law firms?

Here's a story from ABA Journal about the General Counsel Roundtable's suggestion that the biggest national and international firms should have a separate regulatory regime.  My view, fwiw, is the profession would be better off without two sets of rules, but the drafters of the rules need to be more creative in using the comments to accommodate the very different considerations apply when lawyers are negotiating with sophisticated clients that are represented by teams of sophisticated, in-house lawyers.