At the moment, for me at least, combat logging is the biggest problem. A lot of other issues people have with the game stem from combat logging. The rampant KoSing is largely due to the fact that anyone can combat log at any time, server hop, then come back and flank you. Its much safer to outright kill someone even if they haven't spotted you yet. 3 of us who were heavily geared were gunned down earlier tonight by people server hopping and logging back in from behind us. Dying in DayZ is always painful, but dying from people who are taking advantage of broken mechanics is far worse. Sadly, at the state the alpha is in at the moment though, the people who abuse these mechanics are the ones getting ahead. :(