Unfortunately, that's both a strength and a weakness. It's a strength because it allows players the versatility of complexity in this one class. It's a weakness because the character archetypes aren't defined as clearly as some would like them to be. Mearls himself expressed it as one of his bigish regrets with the 5e PHB.
What really gets me, though, is that people openly deny this--they say Mearls is just flat wrong. If the/a lead designer is openly disappointed about something she or he feels is lacking in the game as written...I mean, it's an opinion for one thing, but it's also an opinion from the closest possible thing to an "expert" on the subject. He's got the inside knowledge, be it survey info or simply designer awareness of what's going on. If he regrets the lack of strong identity in these things, it's probably for decently good reasons.
I thought they weren't different enough at first, but as I've seen them play, I've noticed the characters they gravitate towards portraying tend toward different types. Mostly because the Battle Master appeals more to tactical players, and the types of characters tactical players play tend to be tactical characters. In the past, that was the Wizard's job. Now the Fighter can be tactical too (obviously, I'm oversimplifying the story of how we got here, but you know what I mean).
I find the tactical-ness comparison...inapt. Initially, you have 4 dice. Based on the expected number of short rests per long rest (2 to 3), that gives you 4*(1+2) = 12, perhaps 16 dice. That compares...moderately well with spells available; a 3rd level Wizard can cast four 1st-level and two 2nd-level spells, plus an additional 2 spell levels' worth of recovered spells (either two 1st or one 2nd). 7-8 spells vs. 12-16 dice means between 2x-2.5x as many "special things" done, theoretically balanced out by spells being more impactful and far broader plus Fighters having solid (if largely un-tactical) baseline features. However, by the time a BM is getting his second die (7th), the Wizard has four 1st-, three 2nd-, three 3rd-, and one 4th-level spell, and can recover an additional 4 spell levels (one 4th, 3rd+1st, two 2nd, one 2nd and two 1st, or four 1st); even with three short rests per long, that's 5x4=20 dice vs. 12 minimum spells (the lower number being more likely, as recovering higher-level spell slots is more valuable), and more likely only 15 dice vs. 12 spells. By level 15, it's at best 6x4=24 dice vs. 18 spells + ~2 recovered spells, and more commonly only 18 dice vs. 20 spells.
Yes, this gives Fighters some presence in the "resource management" stuff, which in 3e-and-before was almost exclusively the province of casters (and Wizards especially). Maneuvers really don't strike me (heh) as particularly tactical though--you want to use them quickly, and you want to go for the ones that are as universal and impactful as possible (which, sadly, is only like 2-3 of them...enough that you'll have all of them by level 7, if not from the very first...er, 3rd, I should say
). Their "scaling" is sharply limited, and you never get to pick from a broader, more comprehensive, or more powerful set, so they lack nearly all of the long-term planning present in spell selection. And since basically all of them are just riders on top of a successful attack (or preparation to make sure an attack is successful), and they have literally no other use, you may as well just throw them on ASAP when monsters still have most of their HP.
For comparison, I consider the Paladin "Divine Smite" ability dramatically more tactical (albeit still a bit dull for my taste) because you're having to make a difficult decision: keep the spell slot, which has a variety of uses and can make a dramatic difference in the right context, or get the smite damage, which can kill a difficult enemy quickly and thus prevent bad things from happening in the first place. Superiority Dice don't get this tension between "unknown open-ended utility later, or concrete and focused utility right now." It's merely a choice between "use it now, or use it later, and hopefully don't waste it," which is dramatically less tactical.
Interesting, but i think this is exactly what i think makes the current classes so versatile and flexible. In 4E i.e. this was completely reversed. You'd need a hell of "liberated" GM to do anything outside the box. The rules were so "tight", the classes so shoehorned, you were stuck given roles even if you had plenty to do with your PC 9on paper). I actually find the 5E back to the roots approach "liberating".
Yeah...this is gonna just be one of those things, I expect, because my feelings are
diametrically opposite. I see this as being "liberated" from having something you
know you can do well, while still being completely able to employ imaginative solutions (that were actually backed up with solid, balanced adjudication!). Incidentally, it's really not true that you'd need a "liberated" GM. 4e had Page 42, which provided open-ended, scale-able adjudication for almost any kind of combat stunt you wanted to try, which made them not only achievable (many GMs don't understand how probability works, and make things far too hard by accident), but actually worth doing (damage scaling was roughly on par with an Encounter power, helping to avoid feeling like the action was "wasted.") There were also Skill Challenges, which were a good try, though they did take a while to reach actual "balance" and the devs never really made full use of their potential, sadly.
