The deal signed earlier today in Ukraine calls for a return to the constitution instituted after the Orange Revolution protests (but later reversed). Those provisions significantly weakened the presidency–mainly by giving the president essentially no discretion in the choice of a prime minister, who was defined as the candidate of the legislative majority. On the other hand, the president under that constitution still retained control over key ministries, such as interior and defense, as well as a veto requiring two thirds to override. So the protesters are right to be skeptical, even if this is a big concession by President Yanukovych.
The agreement also mentions reforms to electoral laws, but does not clearly address the electoral system itself, which is obviously critical inasmuch as it determines how votes are translated into seats in empowering the very legislative majority that would appoint the PM. And, as I noted before, the current system is highly disproportional and personalistic, and these features allowed the pro-Yanukovych bloc to win a majority, counting pro-Yanukovych “independents” (bearing no party label), despite the president’s Party of Regions having barely a quarter of the votes. Of course, with the renewed mobilization of the opposition, it is less clear who would benefit from the current system’s disproportionality, but the opposition would seem to have a clear interest in a return to the party-list system used in 2006 and 2007. And that system’s proportionality would presumably offer the pro-Yanukovych forces a hedge against possible voter retributions whenever the new legislative election is held.
The agreement also only specifically refers to early presidential elections.
Obviously a situation still in flux.