In my opinion, the best way to sort out a Warlord in 5e would probably be:
* Use Rogue chassis.
* Sneak Attack becomes something like "Warlord's Gambit" where the Warlord can designate one PC to get Sneak Attack as an immediate action (spending a subsequent immediate action to change it).
* Sub Thieves Cant for dealing with military personnel/hierarchies.
* Sub Cunning Action for (a) having the game actually have functional, encoded Cohort rules where (b) the Warlord can having 1-3 Man-At-Arms (scaling with level) that they can spend a Bonus Action with each turn to Move or Help. Subclass will help you trick these Cohorts out.
* Sub Expertise and Reliable Talent for a mundane Iteration of Bardic Inspiration.
* Sub Uncanny Dodge, Evasion, Blindsense, Slippery Mind, Elusive, Struck of Luck for fitting Warlord type stuff. 5e tech that is thematically in line with this stuff from PbtA and FitD games:
Seeing Red
When you discern realities during combat, you take +1.
Evil Eye
Requires: Seeing Red
When you
enter combat, roll+CHA.
On a 10+, hold 2.
On a 7-9, hold 1. Spend your hold to make eye contact with an NPC present, who freezes or flinches and can’t act until you break it off.
On a 6-, your enemies immediately identify you as their biggest threat.
I Am the Law
When you
give an NPC an order based on your authority, roll+Cha.
On a 7+, they choose one:
- Do what you say
- Back away cautiously, then flee
- Attack you
On a 10+, you also take +1 forward against them.
On a miss, they do as they please and you take -1 forward against them.
Setup Strike
When you hack and slash, choose an ally. Their next attack against your target does +1d4 damage.
Ever Onward
When you lead the charge into combat, those you lead take +1 forward and +2 armor forward.
FORESIGHT
Two times per score you can assist a teammate without paying stress. Describe how you prepared for this.
You can narrate an event in the past that helps your teammate now, or you might explain how you expected this situation and planned a helpful contingency that you reveal now.
CALCULATING
Due to your careful planning, during downtime, you may give yourself or another crew member +1 downtime activity.
If you forget to use this ability during downtime, you can still activate it during the score and flashback to the previous downtime when the extra activity happened.
MASTERMIND
You may expend your special armor to protect a teammate, or to push yourself when you gather information or work on a long-term project.
When you use this ability, tick the special armor box on your playbook sheet. If you protect a teammate, this ability negates or reduces the severity of a consequence or harm that your teammate is facing. You don’t have to be present to use this ability—say how you prepared for this situation in the past. If you use this ability to push yourself, you get one of the benefits (+1d, +1 effect, act despite severe harm) but you don’t take 2 stress. Your special armor is restored at the beginning of downtime.
INSPIRING CAPTAIN
Your allies recover from harm faster. They permanently fill in one of their healing clock segments and take +1d to healing treatment rolls.
LEADER
When you Command a cohort in combat, they continue to fight when they would otherwise break (they’re not taken out when they suffer level 3 harm). They gain +1 effect and 1 armor.
This ability makes your cohorts more effective in battle and also allows them to resist harm by using armor. While you lead your cohorts, they won’t stop fighting until they take fatal harm (level 4) or you order them to cease. What do you do to inspire such bravery in battle?
That should do the trick.