Troubleshooting: first identify the problem, then suggest an adjustment. The first part is more important than the second. So here's my problems (some have been prevalent since 2.x, some are new):
(Spoiler brackets are suggestions)
Warrior: Fracture WS limitation. Beyond small uses like a burst window snapshot I don't think Fracture is getting used as it was intended. It's Warriors only DoT and I wish this limitation was changed in 3.0, but it was left untouched.
A buff I think would be great would be if Fracture - applied after a Eye/Path/Butcher combo - granted a stack of Wrath/Abandon. It becomes an appropriate fourth hit in any WS combo, and would give some flexibility in Stack gathering for WAR burst rotations.
Dark Knight: I think I'm the only one with this complaint... Grit & Shadowskin are re-skinned Shield Oath & Rampart, meh. YoshiP's team have had FFXIV for 2 years, the game itself is 5 years old, and DRK is only the 3rd tank in the game. Yea they've got a lot of oGCDs & the Dark Arts mechanic, but it's not the core of their tanking (really only DA>DM is close). That's the carrot strung up to bypass the fault in the foundation.
I know the Development staff has many creative ideas floating around for a tanking stance and a tank job meta; but my guess is these were suppressed to meet the HW deadline. It's bad enough MCH/AST/DRK have to live with the scarlet letter dichotomy that is 'Extra Jobs,' have no base Class, & a lvl30 start. I hope at this time the Battle Team is getting to put their creativity into re-designs for those skills. DRK has other 'problems,' but this is the one I don't give a pass.
Okay so if you don't agree with me about Grit/Shadowskin being a problem: stop reading now lol.
Grit:
Incoming Damage Reduced by 20%
Dark Knight HP absorb Abilities (Souleater, Abyssal Drain, Sole Survivor, *Reprisal) also increase the DRK's maximum HP (capping at 130%)
Shadowskin:
Incoming Damage Reduced by 20%
Reduce TP cost of abilities by 30%
Duration: 20 15 seconds
Recast: 90 60 seconds
Combo'd Powerslash, Delirium, & Souleater add to Shadowskin's duration by 12 seconds.
Added Effect while in Grit: Incoming Damage Reduced by 20%
Reprisal
Recast: 30 5 seconds
Can only be used while Shadowskin buff is present, subtracts 10 seconds from Shadowskin's duration.
Added Effect while in Grit: DRK is healed for 10-20% of their base maximum HP
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I dunno if listing the ability changes like that was necessary. Probably should just explain the concept: Tank stance 20% mitigation is removed for improved self-healing. Increasing max HP means DRK self-heals are proactive instead of reactive.
But the 20% mitigation of the tank stance isn't completely removed, Shadowskin (while in Grit) makes up for that loss because it functions like Greased Lightning / Blood of the Dragon. Keep hitting the target to keep the Shadowskin buff up (and build a surplus of duration). Reprisal adjustment makes up for the lost of Shadowskin as a tank buster CD. Since it works like Geirskogul, it amounts to 3 Reprisals every 60 seconds. An MT Dark Knight would want to time Reprisal with Souleater just before the tank busters, and an OT DRK could use Reprisal for 100% uptime on the debuff (which would be better than Path since it's not a DPS loss).
Not saying this is what should happen, this is just an example. I've only adjusted 3 skills, but DRK's meta entirely changes with just those 3. It's why I think it's not unreasonable to forsee SE making a big change to DRK meta, since big changes can come in small packages.
Paladin: All the problems of 2.x still exist, but most prominently is SE's encounter design moving away the Tank's Tank focus. T8&T9 RiP, SE is done with defacto solo-PLD tanking. FCOB was the first indication of this I suppose. For the 'new day' situation we're in, how does PLD compensate, Utility or DPS? IMO PLD has the tools (almost) to go either route, but they're incomplete.. PLD needs something.
If Paladin has to stomach having no AOE AND lowest single target burst/DPS for providing party support utility while OT, Clemency could be awfully less punishing. No combo interruption. Maybe even moved OGCD (heals are all about timing).
I'd liek PLD to have a Spell Speed buff via Clemency or Royal Authority - since that improves Stoneskin use too. I earned my Lion mount half-way with stictly DFing Ifrit EX (I might be a masochist). But there, as PLD, I found SS to be a great tool to have while OTing. DPSing Ifrit too much actually forces his Enrage>Wipe, and healers are so backed up with splash damage & mechanics that me SSing the current MT was appreciated. I think the 'healer support' utility for PLD is viable, but - as is - it's just not working effectively. A Speed buff for PLD could work like Ninja's Huton, some mechanic bridging PLD's Clemency/Stoneskin to their core WS GCDs, make Clemency feel less clunky and out of place in their kit. J
If PLD DPS is buffed, it could be limited to comboing off Shield Swipe, so the DPS gain is exclusively MT situations (justifying both DPS+ MT and Utility+ OT). If Sheltron doesn't block an attack (magical encounters or when PLD is OTing) at the end of it's duration - instead of just wearing off, it could deal damage.. Could work like Wildfire in that regard.
I'd prefer something fun for PLD increased DPS over just a straight passive damage increase like a Sword Oath buff. Personally I really miss the 'feel' of the Gladiator class quest line, which had an almost more DPS feel to that guild's crew.
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I'll put suggestions in spoiler brackets, but really I think the thing to discuss is the problems. When it comes to suggestions; yours are as good as mine.