I'll speak from the perspective of maining PLD for almost three years now.

Determination has proven to be a wonderful stat for me, reason being that it has boosted my Clemency and Holy Spirit to the point I felt it worthwhile. It also increases my baselines appreciably, but I have no illusions about ever making it to the "99th Percentile" on FFLogs or snatching the "big d**k DPS" crown from WAR.

As was previously mentioned, Tenacity just doesn't scale in quite the same way in terms of boosting one's DPS. I don't relegate it to the status of a dump stat, but it's not my priority, especially when you consider PLD arguably has the best damage mitigation and CDs of all three tank jobs.

As for "metas" and such, I really pay no attention to them. I'll probably dodge a tomato or two by saying this, but I personally have no use for Dir Hit melds on a tank. Build your character in a way that works for you. If you want to do straight DH melds left and right, be my guest. If you want to meld Tenacity over Determination because that's what works best for the way you play your tank job, go nuts.

I think the less we preached to the choir about what others "should" be doing with their builds and focused more on optimizing our own builds instead, the collective sanity of our community would benefit immensely. But that's just my opinion. :V