I, too, would like more Ultimate Abilities.
I've prepared a list that is complete and utter bullshit since the only balance experience I have is running ttrpg games as a dm fair and balanced, and make a bit of flavorable sense in their function. Just kidding, they all suck, but I do hope they inspire the creators to possibly expand out Ultimate options that we have available, or add additional functionality to what we currently have.
White Mage:
Deny Death: Powerful healers can staunch wounds capable of laying low even the mightiest of minotaur warriors. The Greatest healers wouldn't have let him get hurt in the first place
Grants yourself and all allies a 100 resolve shield, and grants a bonus 20 to Ward and Armor for 4 turns. Should yourself or your ally get reduced to 0 health during the duration, you are instead healed to full health, consuming the buff in the process.
As stated, the Whitemage ultimate is a worse version of Caits due to the mechanics of the game. Cait is triggered automatically because you are a valid target when you go down, and you can't revive yourself if you are dead... So what if you never died in the first place? The idea is a simple one: Auto-Revive spells from the Final Fantasy series of games.
Warrior:
For Frodo Valiant Charge: You Boldly advance into the enemy's ranks, striking hard at each of their number in order to Rally your allies, strike Terror into your enemies, and punish those who would harm your loved ones. None of these strikes will miss, and every felled enemy fuels your conviction
Gains +50 attack power for every enemy in combat, and makes two Weapon attacks against all enemies. After the attacks are done, the warrior gains "Inspiring", +100 initiative, and heals themself and their party for 20 resolve for each attack landed, and enemy felled.
This isn't a berserker wading into a sea of blades with reckless abandon, this is a master swordsman advancing to cut down as many things between him and his true goal: the end of the fight.
Rogue:
Exploit Weakness: You toss forth a small incendiary device packed with Leananstones, spices, (and a few extra surprises) which detonates in a loud, bright flash spreading corrosive powder all over all enemies, making them significantly vulnerable to you and your party's followup attacks.
Would apply "sundered" and "staggered" for X turns, and a new debuff called "Vulnerable" for half of the staggered turns. Any attack suffered while "Vulnerable" is a guaranteed critical hit and causes the target to bleed if they suffer any damage while under this effect.
If Assassinate is a Rogue trying to remove a single hard target while everyone is distracted, this is a Rogue trying to clean house as quickly and efficiently as possible. While weaker initially, with planning, and coordination between party members, this should bring down groups of hard targets with little issue. I feel this is worth an ultimate slot as it sets up a full turn of MASSIVE damage from allies, guest party members, and other ultimate abilities.
Charmer:
Incite Orgy: It is said that the Malachite's "Dance of the Seven Veils" is amongst the most erotically charged displays, able to stir the passions of even the most cold hearted of mortals in the world. It can't a candle to what you can do with the Carnal Arts.
Causes all active participants of the current combat to immediately engage in passionate fornication. This deals all participants 100 resolve damage (your party heals that amount), and leaves your party feeling invigorated, giving all allies a temporary +1 to all stats. You leave all enemies "Weakened", "Bruised and Beaten", and completely "Drained". All effects last until the end of combat. Can not effect targets immune to Lust combat.
My headcannon is that Champion Charmers are both inspired by, and in competition with, Gods of Passion and Lust. And I personally found mid-COMBAT quickies a hilarious concept, and not too much of a stretch given how salacious the 'Tease' attacks can be.
Universal:
Life Break: Your Training with Zo has given you insight into the energies that dwell within yourself... and your enemies. You can strike keenly at the core of someone's essence, significantly disrupting their energy and potentially ending their life immediately
You make a single unarmed melee attack at +500 attack power, ignoring armor, and striking their Ward. Survivors are weakened and fatigued for 3 turns. Should your bring an enemy below 20% of their maximum health with this attack, they are instantly slain. (Bosses are immune to the instant death component)