That's true though. The "Essential" online features would be Trading and Battling. Things like the Union Hall, or even a GTS would just be additional items. Though, in all fairness, if you've done the other ones, the things such as chatting, Entralink and so forth would just be derivatives on the same principle of communication in Essentials games. In short: if you've done the one, it would be straight forward to do the other.