The lag problem with FFXI in Ody and Dyna D was because:
A) lots of western players use Gearswap that automate gear swaps fast
b) everyones client has to be updated with all the changes from gearswaps (HP/MP)
c) you keep adding random hp / mp to armors when you don't have to
Suggestions to fix this going forward:
1) Stop adding random hp/mp stats to gear, there should never be +/-hp or +/- mp on gear unless it needs to be there as the main function of that gear. Equipping a accuracy neck should not also take -10hp. Every time anyone in my group puts that neck on my (and everyone in the alliances) UI has to be updated with that -10hp and then back to normal. If that's in a weapon skill macro they are going to be doing that every few seconds.
2) Make all players MP bar to ZERO if their jobs have no spells and are not using a mage subjob. A sam/war should not have an mp bar at all (merits should not count either, nor should gear), because having it is feeding my ui worthless information that needs to constantly updated and when the game has a 56k data connection cap that's a big deal.
It happens whether players use gearswap addon or not, because one person in the group using it will spam everyone elses UI with the constant stat changes sent to us by the server to update our UI. I don't use gearswap but when I do dyna D I lag cause my party ui hp/mp bars are bouncing around constantly from people who do use it.