Cavalier and Scout don't get to use Maneuvers. So while the base mechanic is the same, what they do with it is different. If using Superiority Dice means you are a Battle Master than using spells means you are a Wizard.
I don't see much distinction. What's the difference between the second Superiority Die option on each of the new Fighter classes and Precision Attack? Or between the third option for the Cavalier and Trip Attack?
It would seem like three new Manuevers would cover all of these options:
1 -
Great Skill. When you make an ability check, you can roll your superiority die and add it to the result (maybe limit this by "that you are proficient in," maybe not). Add the die after you roll, but before success is determined
2 -
Agility. If you're hit while wearing light or medium armor, you can roll your superiority die and add it to your AC. If the attack still hits, you take half damage from it.
3 -
Protection. If an ally within 5 feet is hit by an attack, you can roll your superiority die and add it to their AC. If the attack still hits, you take half damage from it.
(not convinced those last two can't be rolled into one)
I'd generally prefer them using existing mechanics to model fiction where it is appropriate rather than inventing new ones. There's room for non-BMs who use maneuvers, but the escape velocity for them is pretty high, IMO - the distinction they need is more than "new manuevers."
Like, you could use a Ranger subclass that used superiority dice and manuevers for a more "tactical ranger" feel. That'd probably be meaty, in the same way that the distinction between Wizard and Sorcerer is pretty meaty. But "I'm a fighter who can use superiority dice on some skill checks" isn't a much different from "I'm a fighter who can use superiority dice on my attacks."
Could be something I'm missing, of course!