There's room for lots of types of BMs! I've had more than a few myself over the years.
That's part of why the Scout and the Cavalier are having problems here I think!
Everyone else who uses the BM manuevers is saying, in some way, "your BM CAN'T be this." Expanding the BM manuever suite is saying instead "BMs are a flexible subclass that lots of different characters can be."
Klaus said:
Not *everyone*, but the Superiority Dice is possibly the most iconic expression of "martial" power in this edition.
I don't know that I'd totally agree with that. It's one subclass. I know spellcasting is pretty ubiquitous in 5e, but SD doesn't seem any more part and parcel of "martial power" in 5e than the Champion's improved crits or the assassin's Assassinate.
From where I'm sitting, "action economy" is where martial classes dominate - through Extra Attacks, through Action Surge, through "bonus action actions" (from the monk and the rogue), characters that don't use spells tend to fit bigger effects into a smaller space than other characters can.
I think it'd be interesting to see a subclass that does more with the action economy, rather than relying on cribbing from the BM's notes.
Something like...(THESE ARE NOT BALANCED AT ALL THEY'RE JUST CONCEPTUAL)
Mounted Mastery. As a cavalier, your mount becomes an elite fighting machine. You can use your bonus action to give allow your mount to take the Help, Disengage, Dodge, or Attack action.
Agile Defense. As a scout, you're able to defend yourself well in light armor. When you are in light or medium armor, and you are hit by an attack, you can use your reaction to cause the attack to miss. You can use this feature a number of times equal to your Dexterity modifier, and then you must finish a short or long rest to recharge the feature.
Same ultimate goal of some of the SD features of each subclass, but mechanics that are more innovative than "loot the BM."