The Paladin job is the paladin only in name now. Pure salt and sadness.

[Rakshazi]

OP, if you are comparing any job to their ARR varient then you are doing it wrong. ARR was by in large a completely different meta. PLD in ARR had a 3 button combo (boring), and not as much ultility as you might think. Over the many expansions, PLDs identity has only improved, and while I will agree that SB PLD is better the ShB PLD, our identity is very much intact.

The identity that has been added since ARR (and further enhanced in ShB)
- Holy Magic: I hated that ARR PLD was a glorified GLA, I wanted spells, and MP usage, and flash didn't cut it. Now we have Clemency, Holy Spirit, Requiescat, and as of ShB - Holy Circle and Confiteor as well.
- Utility: While yes, some of our defence has been cut, our utility is still there. We have cover, intervention, divine veil and clemency.

As for similarities in playstyle, I'm not sure what other tank has two burst windows one of which turns PLD into a caster job.

-Who told you that PLD isn't a glorified GLA? IT IS. We playing paladins, not the battle mages! It's ok to have blesses, protection and healing magick! Some Smite-like buffs to damage, but not AOE DPS!! It's nonsense! Even based on lore we have in game paladins are ROYAL GUARDS (Guards means that we guard, protecting, not throwing DPS spells around), not Royal Battlemage SWAT.
- Clemency, Passage of Arms and Divine Veil (basicaly everything before ShB) are the only Paladin-like actions we have now and they are OK. Cover is barely EVER used so i'ts basicaly useles.
- Every tank now have DPS windows with gauge filled. EVERY ONE. The thing that it turns PLD in caster is buggs me even more. PLD is not the job that damages, it's the job that protects. And instead of giving stupid DPS spells it's better to give it ally enhancing blesses and buffs or debuffs to an enemy so the party DPS will not fall down.

Defending the party from what?
I hate saying this sort of thing, but if you want tanks that focus on defense you may wanna look elsewhere. This game simply does not have enough damage floating around in order to support that kind of defensive play style. They would basically have to redesign combat, the game over and nerf healers into the ground to even begin to warrant it. Replacing Pally's skills with defensive abilities would just end up with bored healers, longer instances, and alot of angry pally players.

Mate, have you ever played some high-end trial with at least few people haven't died in it because of AOE and player mistakes? Believe me, if there was some PLD action, that could mitigate some damage for everyone in a line of boss - PLD - party it would be apreciated.