Recommended gear feature, recommending wrong gear?

[Niwashi]

Not quite every way:

Mythril Cuirass (HQ): Vitality +10
Sentinel's Cuirass: Vitality +9

It appears to be weighting the 1 point of Vitality above the 25 points of Def and Mag Def, 1 point of Strength, and 1 point of Tenacity. Well, VIT is your primary stat, so I can see it outweighing most of that. The 25 points of Def/M.Def is kind of pushing it, though. I think I'd prefer the Sentinel's overall.

[MistakeNot]

Not quite every way:

Mythril Cuirass (HQ): Vitality +10
Sentinel's Cuirass: Vitality +9

It appears to be weighting the 1 point of Vitality above the 25 points of Def and Mag Def, 1 point of Strength, and 1 point of Tenacity. Well, VIT is your primary stat, so I can see it outweighing most of that. The 25 points of Def/M.Def is kind of pushing it, though. I think I'd prefer the Sentinel's overall.

Indeed. From what I can tell the "Recommended Gear" will always recommend the (usable) piece of gear with the highest amount of your primary stat - which is VIT for paladins. Only if two pieces provide the same amount for your primary stat will the recommendation algorithm look at any of the other stats.
This usually will give a good recommendation, but there are a few exceptions. Low-level tanks often get dubious recommendations because so much gear provides VIT even if it is not tank gear.