Here's some Changes I wanna See generally, this is just my opinion right now, I want PLD to feel like a "Combo tank" with having different and seperate, combos somewhat like it used to with how you had two different finishers and atonement felt a lot less spammy as you didn't use it that much compared to now.
1. Free Up some space, Circle of scorn, FOF and some other abilities could be removed/reworked.
2. Add a Savage Blade > Goring Blade combo, this will give you the effect of "fight or flight" for 30 seconds, which can be stacked up to 60 seconds, this could either boost damage, slightly speed up skill speed & spell speed or do a bit of both, this means removing FOF button, but making PLD's goring blade have purpose.
3. Reduce atonement down to 2 Uses, Allow doing two atonements to give you one stack of "Divine might", You can hold up to 2 Stacks of Divine might now, Atonement doesn't break combo also and gives out more MP.
4. Improve Niche Abilities, Cover you could extend the range, make it cost no gauge and share any healing effect the PLD gives out, Clemency you could make a OGCD targetable heal that coosts around 3000 MP, so you could still spam it in situations at the risk of your own DPS by having no MP for spells this makes MP management more of a thing on PLD, Shield Bash could be a OGCD stun that does damage with two charges that stuns aoe (Its even OGCD in pvp I believe), Passage of arms should be reworked, Divine veil could give out a regen instead of that 400 upfront healing, last but not least Oath gauge should feel more rewarding to the Job, auto attacks? My idea is using shelltron/Sentinel should reward you with extra Gauge.
5. Make the Job FUN at early levels, I really don't get why a lot of jobs got to feel awful to play until your in stormblood/shadowbringers... Just makes synching down feel terrible.
On point 4, I might see how we could also nerf somethings as all those changes complied together would make PLD really strong, many ideas like Removing self healing from magic attacks and only giving you a bit on atonements (200?) or something, I don't know I want to see PLD as a strong support/utility tank without Making it too powerful, I think one thing is we could have the longest Invul still to counter some strengths, also PLD should be very slightly behind DRK/GNB (but not to the point where PLD becomes useless).
I know most people might not agree with every change I've listed but Ideally we all want better for current PLD.