They are already adding it to the export function - hooray, because I was sorely missing this in the split of my regular Google account from my GA account. The third paragraph reads:

   We think the end result is better than what's available today, 
   and you can sign up for Google+ right now to start prepping 
   Reader-specific circles. We recognize, however, that some of you 
   may feel like the product is no longer for you. That's why we 
   will also be extending Reader's subscription export feature to 
   include the following items. Your data belongs to you, after all, 
   and we want to make sure you can take it with you.

   * Your subscriptions
   * Your shared items
   * Your friends
   * Your likes
   * Your starred items