What they mean by "change the damage calculations of tanks"?

[Alahra]

Frankly, I don't see why they just don't come out with a hybrid accessory if they tend to go a 50/50 route.

They could only do that if they locked accessories by class, though. If they put in STR+VIT accessories, DRG and MNK would have decent reasons for using these accessories during progression to ease into HP/VIT checks, which recreates the issue of one role wanting another role's accessories, and also gives those two classes advantages over all the other DPS when it comes to progression content (where surviving raid-wide AoE can be a big deal).

[Nektulos-Tuor]

They could only do that if they locked accessories by class, though. If they put in STR+VIT accessories, DRG and MNK would have decent reasons for using these accessories during progression to ease into HP/VIT checks, which recreates the issue of one role wanting another role's accessories, and also gives those two classes advantages over all the other DPS when it comes to progression content (where surviving raid-wide AoE can be a big deal).

Simple Fix.
Give all accessories 1/2 the Vitality of its main stat rounded up.
Give Tank accessories 1/2 the Strength of its main stat rounded up.