If I was the President, I'd ban the use of e-mail within my administration. Having White House e-mail be subject to open record requests makes sense. It's like a memorandum - it forms part of the paper trail which any office leaves behind as evidence of its activities.
Memorandums are the lifeblood of government.
They are how things get done, as well as how folks get caught when things go wrong. To hold government accountable for its actions, you must have access to the memos. You see, the problem with e-mail is that it is far too convenient. Composing and sending an e-mail requires so little thought and effort that most of us assign it an importance roughly equal to that of breathing. In other words, we all know intellectually how important it might be, but we never really think about it while we're doing it.