[Zensation]

I was reading(link) that with halogens, the more of a nucleophile it is, the better its leaving capability - with iodine being the most nucleophilic halogen and the best at leaving.

So, would halogens on a molecule that are near electron donating groups be better leaving groups, or worse leaving groups, than if the donating group was not nearby?

I would assume that the halogens nucleophilicity would be increased by nearby electron donating groups and thus become a better leaving group, but this contradicts the principles of Nucleophilic Aromatic Substitution reactions, which go over more effectively when electron withdrawing groups are in close proximity. I don't understand how an electron withdrawing group can increase the nucleophilicity of a halogen, and thus its leaving capability.