I agree - I tried to outline what I could based on what I came up with as the problem with PLD, and I think as the thread developed we got a better idea of everything that was going on here. WAR is definitely the best tank hands down right now and that is an issue for both GLA and PLD. That being said, it is also the case that GLA is better than PLD because of a few things all adding up (which while I would commend anyone who reads all 16 pages of the thread, I'll try to sum up here real quick):
1. One of my main points, PLD relies heavily on MP to stay alive, yet has no way to recover it on it's own. GLA on the other hand can recover MP, and has better and less specific abilities to keep it alive (such as evasion boosts and instant cures, rather than just cure spells). I simply made some suggestions as to how PLD could have some MP recovery without it being too ridiculous. Outmaneuver is already meant to offer this, but in practice does not.
2. One of the primary rebuttals of my argument was that PLD just needs a BRD to give them Ballad, or a THM to give them Sanguine Rite. While this definitely addresses the lack of MP recovery to PLD on it's own, it ignores the fact that both of these methods also work on GLA, allowing for GLA to do more with it's MP. Another common response to this was that this would likely prove risky for a BRD or THM to do in a fight where it would be critical, as they could run in at the wrong time and get hit with some massive AOE that a tank can survive but they cannot.
3. Another point some people started to bring up was that PLD can gain enmity better than GLA. In my opinion, this is not the case. All raw enmity abilities are accessible to both PLD and GLA, and I have yet to see issues with enmity that would require a heavy duty cure to get hate back. Others echoed this. For me personally, this argument is even less valid as I typically run with a WHM that ends up getting cures off faster than me in most cases, or at around the same time. The best use for curing spells I have is when he needs to do something other than cure me, and tells me to keep myself alive.
4. The chatter about abilities aside (about which both sides seem to disagree, and I haven't seen many people swayed in the other direction), the next thing we come to is the loss of HP with a promised defense boost. Unfortunately, and this is one primary reason why WAR beats PLD at tanking right now, PLD's loss of HP results in an unnoticeable gain in defense. This means that where PLD was intended to have this supreme defensive ability at a sacrifice of its HP, which would have worked. If this were the case, PLD's loss of self-sustainability moves would not be as severe, as the idea would be that you're taking less damage overall so putting less strain on your healer(s).
5. As I touched on in my OP, I also feel as though block rate for PLD (and GLA to a degree) is just way too poor. There was a suggestion that the dLvl penalty on block rates is likely too harsh, which is probably the culprit here. My point is this - compare a GLA/PLD to a MRD/WAR, the difference is one uses a one handed weapon and a shield, while the other uses a two handed weapon. This would suggest that GLA/PLD are spending half of their focus on their shield, while in-fact we barely block at all. This coupled with the fact that MRD/WAR can parry as a replacement for blocking, makes shield's just seem rather silly right now. As an extension to this, Outmaneuver is also useless as it does not seem to do much in terms of increasing block rate, and the MP return is rather insignificant when compared to MP costs at level 50.