Also I hadn't even considered Dark Ether. That strategy...really didn't seem that good to me?  Like, it seemed okay, but not that impressive?  Of all the strategies to keep, that one seems least interesting. Then again, Ninja has to be able to do something.  I don't feel like they had a defined niche at all.  A good choice for sub-class on several, but not really a great base class.

Why not change Yggdroid, though?  Yggdroid could be a sub-class. Even if it couldn't, who's going to lament one less option as a sub-class?  Not me.  EO4's subclass system, and to a lesser degree even EO3's, had pretty clear-cut "best answers."  You could play around, but there are obvious correct subclasses for each unit.  Who's going to run not-Imperial on Runemaster?  Who's going to run Medic on Landsknecht?   It's open-ended, but with fairly "Correct" answers, just a bit more variety, but a much higher potential to mess up if you don't know what you're doing.  Yggdroid almost makes more sense under such a system.   They have good passives but almost nothing else going for them; they're perfect to ignore as a sub-class and perfect as a main class that can't really pick a bad sub-class.

Bushi had no reason to be excluded.  I'm going to continue hoping for DLC.  But in a more real-world question, the Vessels were the closed-off ones that didn't trust easily, and the Bushi were the humans' bros.  Why would our bros not follow us to the new location, but the people who didn't trust us would?  Doesn't make any damn sense.

Whip Dark Hunter is plenty distinct, and even their sword-focused ones had the bait traps and the healing, so that's distinct as well.  Nightseeker is an entirely different class.  Their focus is on damage through ailments, while Dark Hunter is either damage through binds, or status support stall.  It's silly to consider them too similar.

Dark Hunter and Arcanist would've paired beautifully.  Basically, I think it would be the inverse of Arcanist and Harbinger match-up.  Harbinger will likely also focus on ailments (or so I hope, but then they're REALLY similar to Nightseeker), in which case Arcanist can focus on Bind circles.  Replace Harbinger with Dark Hunter, and the Arcanist just focuses on ailments instead of binds.