From Wikipedia regarding the 2004 Ukrainian Constitution - amendments were passed at that time that rolled back a lot of the powers of the Presidency. Such as:

The 2004 amendments weakened the power of the President of Ukraine; she/he lost the power to nominate the Prime Minister of Ukraine and this became the task of the parliament solely. The President could only appoint the Minister of Defence and Foreign Minister. The President also lost the right to dismiss members of the Cabinet of Ukraine but gained the right to dissolve parliament. If no coalition in parliament could be formed to appoint a Prime Minister the President would have no choice but to call new parliamentary elections.

By going back to this, Yanukovych has lost some important powers. While it doesn’t reduce him to, let’s say, a purely ceremonial position, it does put some significant curbs on him.