From the (old) FFXIV 2.0 page:

Enemy leader and group systems to be removed before version 2.0.
Enemy "call for help" system released in patch 1.19, causing nearby enemies to link when called.
Release of a system to calculate enemy strength based on party size and member levels. Enemy "call for
help" system to be adjusted in patch 1.20 so only appropriate enemy types link.
I am not sure if the bolded sections have been implemented already or scrapped till 2.0.