In 09 and 10 there was no big 4 really. Murray nor Djokovic made a slam final in 2009 with loses to players like Haas, Roddick, Gonzalez, Cilic...2010 was more of the same for them though they made slam finals 1 each. Djokovic won just a single masters title in that entire 2 year period and didn't record a win over a top 10 player in 2010 until September. Neither Murray nor Djokovic were particularly stronger than the top contenders of Federer's era if at all in this period. For example Djokovic in 2007 was playing better than in 09 or 10. The field didn't get stronger till 2011 really.