Originally Posted by
Tyranastus
It depends on the circumstances behind your acceptance into the guild:
If they were recruiting to fill a permanent spot and that spot is the one you are currently in; yes, you leaving for a better guild is a dick move.
If you asked to join them and their raid team, and they said that they were just raiding for fun and just to optimise heroic gear on their raider, so come along for some gear if you want; no, it's not a dick move.
Essentially, if you gave them any indication of some form of ongoing guild and raid membership, or joined under false pretences, or will be leaving the guild that has helped to gear you in a poor state; you may in fact fall into one of the categories of what is wrong with organised raiding within current WoW. It sounds harsh, but it's just the truth. And honestly, if you have to ask the question, I am going to assume that your conscience knows all of this already.