I had fun being wrong before the season started, so let's play "guess which armour astir playbook might suit Keith's new pc" (spoilers for some patreon stuff if you don't listen to that)
So, Keith is probably playing leap again. If that's not true then obviously I've no idea what will happen, so let's take it as true for now. Leap was the infiltrator, which was a class about handling dangerous situations and that dealt well with being outnumbered. Leap then became a pirate captain.
None of the core rulebook classes work. From encore there is I think only one real possibility, more narrative than mechanical. The commander could bring in leap's pirate crew, as well as his scrappy and defiant nature.
Beyond that... I've had a quick look at some of the fan playbooks.
The brigadier from 106th squadron final mission by yuri runnel has similar vibes to the commander (except maybe even bleaker?), so if I think the commander potentially works that might too.
Prototype: Experimental Astir Technologies by This is not a table has two that I could see working.
The ascetic, which is about being a hard worker who makes their aster run without magic, could be a fun role for leap to fill in a team that's very magic.
The gunslinger is about someone with a signature weapon, which I don't remember leap having, but 1) time has passed and 2) Keith likes a signature weapon.
Finally, for full goofiness, they could lean into the leap heals clem scene and give leap the medic class from one of yuri tunnel's other playbooks collections.
And of course, maybe leap has magic now? That would be sick as hell, even if I have no idea what would suit. I'd love to hear other people's theories.
There's also the possibility leap will have a class from an as-yet-unreleased playbooks, or one my search didn't find. More things under heaven and earth etc etc.
I think out of all of these I'd find ascetic or commander most exciting instinctively, but I'm basically excited to see what unexpected answer the show comes up with.