hard to say. because federer mainly got his points from 6 events. the four grand slams, madrid an cincinnati.
to hold the n1-spot he would have to replace the ~4500 points until after the french open.
(he won ~5'400 in this years period until the french open)
I don't think we can settle it before the french open is over. also hard to say who the toughest n2 is. nadal? (the most points to defend) djokovic? (was pretty good last year but screwed up the GS, can he do better?
murray...nah, don't think so. del potro too early.