I am rather puzzled by Nikolic's hunger/thirst strike in Serbia.
First of all you don't protest to change generally election laws. Sure, sometimes most people agree that the present government is stupid. But that is bad luck: election laws are there to be respected. A government has the right to end its period. If you don't respect that you don't respect the rules of democracy.
That doesn't mean that there aren't ways to undermine the present government and to force elections: The present government is a coalition. So it might be possible to find a coalition partner who might benefit if it leaves the coalition now. An alternative is to field proposals on which the coalition is divided or on which the coalition has chosen a difficult to defend position. The budget proposals by Ryan in the US were a good example of how to do this.
Of course the government parties still have an advantage and if they play their cards right they can prevail. But the opposition has the advantage that they can choose on which subject to fight and doing that they can push the government in the defense.
Nikolic's present action will weaken his standing with the EU and the US (and we know how important their input was in previous elections).It will also weaken his standing with the Serbian voters who value democracy. Even if he gets everything he wants this action may bring Nikolic more harm than good. Making threats is not the way to get things done in a democracy.
In my opinion Nikolic should as fast as possible find an excuse to end his hunger strike and lead the opposition again. It may cost him some voters in the short term, but continuing this charade is more damaging in the long term.