Just because OP has mentioned it already it doesn't mean it should be neglected:
Classical case of:
To compete on world bosses you have to bring in the same amount of dedication and tryhardiness and there is nothing wrong about it.
How members of a guild that has been using this practice on other projects for a very long time are the ones screaming abuse now is pretty damn funny to me.
How about you get your guild to not suck every once in a while, maybe you actually get enough people that will care about World Bosses then.