A tad confused on what it is you’re looking for in a plate class but since my only other ‘main class’ is paladin these days I’ll chime in.
Warrior -
Arms - Easy enough spec, two handed DPS, you get to shout to buff allies or scare enemies, what’s not to love? Solid in PvP (with a healer) usually if that’s your thing. Lower APM than fury by a fair margin.
Fury - whirlwind of steel, high APM, DUAL two handers! Iirc it was maybe is looking promising for DF?
Prot - great simple enough tank imo, the new self heal makes it even better imo. Sword and shield stalwart knight kinda thing uses rage to buff defences, can charge to allies.
Paladin
Prot - captain America style shield throw, hammers, heals!, justice! Light! Very fun, easy enough to play and solid defences plus a good amount of ‘oh sh1t!’ Buttons! BIG glowing wings!
Ret - Eh love it or hate it. Burst then wet noodle, slow but loveable, self sustain, BIG Glowing wings! Utility which I love most about it!
Holy - well you said you’re not interested and probably good as imo it’s a healer that’s stuck in limbo atm.
DK
BDK - Vampiric tank, plagues, Blood siphoning, grip! Kind of like an unstoppable juggernaut although not so much unstoppable these days. Still my favourite tank spec.
FDK - very fun dps, simple rotation and beautiful spells, breath looks great! Frost themed if that’s your thing and can wield a two hander or dual wield one handers - can’t remember if there’s a benefit or not to one as haven’t played it in a long time!
UHDK - Pets! Minions! Gargoyles! Abominations! Ghouls! Plague spreader, think Necromancer only a hulking plate behemoth unless you play gnome. DoTs though not an insane amount, interesting DPS.
In all honesty you can’t go wrong with any of the above. I personally love paladin for its redemption kinda theme and faith. It’s very self sufficient and has great mog selection + it feels very smooth and easy to rope into if I’m burned out on Druid.
Warrior is a good old fashioned no magic fest, you can’t really go wrong with it. You get a leap, charge, shouts and buffs. Very useful and fun to play.
Pick what calls out to you or you find most fun. I love paladin, but BDK tanking as above is my personal fav I just prefer Ret for DPS in PvP or PvE. I also love the fact Paladin has a heal/tank/DPS spec so you can never get bored 