Not out of date, just because it's rarer, doesn't mean it can't tank and wasn't used as a tank(as you claim, but have already admitted that they have at some point). Also, sky gods, kirin(who spammed aoes), sea gods and both section of limbus were all end game at 75. All of which SAM has tanked before, including some HNM's in the WOTG era. Rather their relevant or not at the moment doesn't matter, as this content made up a majority of the games life span.
Sorry forgot about the fact RUN has a weapon that takes months to years to make. Also see point address your souveran cuirass gear. Since RUN you know, can't wear it at all or any heavy armor for that matter and are stuck in the lightweight and middle weight armors.
Why was ninjas ultimate weapon suited for dps when players obviously made that class into a tank? Why does RDM have access to Excalibur, other than to use as a toy? No one knows, ask the developers.
It's actually about the same for physical damage reduction, and tartarus pulls ahead for magic defense, which by your logic is the worse type of damage along with AoE.
Souveran has like....15 more vit. Tartarus has 11 more magic evasion, 2 more of a traited magic defense bonus(once only on rdm and is on run), and absorbs magical damage by 5%. Oh and 7 more actual defense. --- This is the Souveran +1, that has been augmented.
https://www.bg-wiki.com/bg/Tartarus_Platemail
https://www.bg-wiki.com/bg/Nolan
Not to mention it still destroys your moot point of heavy armor only being stuck on drk,pld, and war.
Also since war can use both, I suppose WAR can tank too and is in league with PLD. But RUN can't use either....so RUN obviously isn't a tank. (sarcasm)
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Thank you.
V. Equipment Sets
a. TP Sets
b. Bow Sets
c. Weapon Skill Sets
d. Defense Sets
From the guide you linked. --- Also this guide is over a year old and doesn't seem to be being kept up to date. ;o
But I see a optimized....-PDT set. a -MDT set....a HP regen set. Oh and lookie here a enmity set, the stat that lets you grab hate. In a 2016 guide for FF11.
Seems all your points are basically irrelevant and some actually fall in line with my own.