The Crusader's flexible kit makes him a great all-rounder for many situations. Six of his seven skills see regular use - only Smite is not commonly used due to the lack of additional effect it carries.
His Bulwark of Light skill now grants a party-wide 20% PROT buff, which is a handy skill to start the fight with as it immediately neuters enemy direct damage. Be aware that it has little use against Stress or DoT teams, and it is bypassed by enemy Shieldbreakers or other sources of PROT reduction. The PROT bonus stacks with the Crusader's innate PROT and can be cranked even higher with the Battle-Scarred Helm or Gladiator's Helm to turn him into a tank with defenses rivaling the Man-at-Arms's.
Of his attack skills, Zealous Accusation is a staple among Stress-focused builds as it can inflict a fair amount of Stress to the front two enemies and even bypass Guard depending on the position. Stunning Blow is also a great shutdown move for frontliners. Holy Lance is commonly seen on Crusaders starting at position 2, as it lets them synergize with other movement skills from the party member behind them, or allows for emergency repositioning if the enemy uses a move skill.
His other support skills have changed, too. Battle Heal is now Rally to the Flame, allowing him to heal himself and one other ally for a small amount of HP - usually enough to push them away from Death's Door - while purging most debuffs from both units. Bear in mind that Rally to the Flame cannot be used if the Crusader is the last man standing. Inspiring Cry now recovers a lot more Stress and provides a lengthy buff that adds to Virtue chance, allowing for a chance at a turnabout should you be confronted with a Stress team.
With only four skill slots to use, pick your skill loadout and trinkets carefully. Supportive Crusaders that take Rally to the Flame and/or Inspiring Cry will find great use of the Glorious Standard which augments both skills and protects the Crusader against shuffles. Stress-based Crusaders with Zealous Accusation will usually be packing the Writ of Execution to augment the Stress infliction. Melee Crusaders find value in the Sacred Blade as it improves raw damage output and raises the Stun rate of Stunning Blow - though the Brass Knuckles can be used as a suitable substitute until the Blade is unlocked.
Pay attention to where the Crusader is and what they're packing. If you don't see Holy Lance at all, you are generally safe in knocking him to the back of the formation to deny most of his attack skills. If they do have Holy Lance, only consider knockback if you really don't want the Crusader Stunning or Stressing your frontliners.
The Crusader is a very hardy unit, and can take a long time to kill, especially if he busts out Rally to the Flame. However, if you keep the pressure on his teammates and they don't have other strong sources of healing, you can force the Crusader to spend a majority of his turns healing the party to keep them off Death's Door. His Stress Relief skill, should you actually encounter it, can easily undo the work of a Stress team, but if you keep a good assault on both body and mind, the enemy Crusader will have to pick between healing or Stress relief to save the threatened teammate.
If the Crusader's the last man standing, he cannot heal with Rally to the Flame, making him easier pickings depending on how the rest of his skill loadout is like. He's also got a relatively low Stun resistance for a frontliner, so Dazing or Stunning him can keep him from coming to the aid of his teammates.