He had been prime minister under Kuchma during the two years preceding the election. A President Yanukovych taking office in 2005 would no doubt have perpetuated the policies of the Kuchma regime, and left most of its personnel in place.
The elites that dominated Ukrainian politics were too powerful, too entrenched and political forces that might have pushed a Yanukovych presidency towards democratic reform were weak and undeveloped in 2005.
Yanukovych came to the presidency in 2010 a much more independent and experienced politician, with a much clearer sense for what needed to be done. And he governs a people who are harder to manipulate and less fearful of standing up to state power.