This is my main reason for preferring to do it nonviolently (Avenue 1). We need to be building things that give power to the currently powerless and decentralize control, not the other way around. If we take power "for ourselves", we find that what we call "ourselves" is infiltrated by the worst kinds of people, and then
they push us out.
I don't have any moral problem with killing the current global elite. For what they've done to this world, they're effectively our property, to do with what we wish. That said, I prefer to offer them full amnesty so long as they decline peacefully. (They'll even remain fairly wealthy; just not dominant anymore.) Even if it's abstractly morally acceptable, there is a major moral cost to violence nonetheless. Once we start it, how do we stop it? Also, violent revolutions tend to draw in the worst people (who are attracted, as noted, by the power). Our side is 99.9% of the world; not everyone in that set is good.
Best is a nonviolent revolution centered on decentralization of power (giving power away to the currently powerless in order to build a healthier and more robust world) because the sorts of people who are attracted to such a movement are the kinds you want. When you start killing people and blowing shit up and "ruling" old-style (see what happened to communism) then you are taking power (perhaps with the stated intention of giving it back some day) and you get a lot of mercenary assholes in your effort who don't really care about the ideals and just want to cause harm.