Agreed rankings don't lie. Right now Nadal is a much better player than Ferrer, but after the AO Ferrer is clearly superior.
Who told you rankings say player A is better than player B?!
Rankings tell you how a player has done in terms of results in the past 52 weeks.
Right now nadal has had better results in tournaments in the past 52 weeks. After the AO Ferrer will have better results in tournaments in the past 52 weeks. Seems pretty accurate to me.