Who started ww1 probably did not matter much, however it ended up being a war to the Death and when it ended the Austrian-Hungarain Empire, the Russian Empire, the Ottoman Empire and the German Empire was gone or would be gone in a few years. So ww1 was an destroyer of empires.
Russia was even on the side that would win but still they lost so even picking the side that eventually won don't guarantee victory.
Either way the whole thing is one of the biggest man made tragedies in history. There was no need for a world war and 20 million dead over Serbia. What did European leaders fear so much in Austro-Hungary adding Serbia to their dysfunctional little empire that was doomed to collapse soon anyhow?
On other hand it got rid of several authoritarian governments and maybe had an influence of the spread of democracy so the end result was not completely bad, however then you have ww2.