I'm A Banana
Potassium-Rich
See, I find this quite inelegant (just like I do the Tri-Vampire), because I personally believe the fluff should mean something. Something specific. If you can be a "Gladiator" just by taking a feat that has you wielding a trident and net, even though you're actually an elf wizard... then no, I think then having another Gladiator being a specific type of Fighter is inelegant.
The meaning depends on the table. Design is local. Maybe IMC there's a group of enslaved sea elves who are forced into gladiatorial combat against their kith and kin, made to fight magical battles for the amusement of the spectators above, and given the very weapons used against the wildlife of their world to beat each other to death with when their magic runs out.
Maybe at my table, there's just one guy who wants to play an elf wizard who used to be a gladiator, but won his freedom.
The game and the designers don't need to dictate the way my table plays, and by making the pieces modular, I can add what's right for me without having to add everything that's wrong. Gladiators in my world are enslaved sea-elf wizards who fight with fishing implements. Do I need to redesign a whole class, or can I just get a specialty I can add onto them?
Pick one or the other. But don't have both. It's my exact complaint with regards to the Fighting Styles / Specialties issues I've talked about in other threads... where you could be a Marksman *and* a Sharpshooter. Or a Reaper *and* a Slayer. Both of them fluff out the exact same way, even though they theoretically should be two different things (since one is a specific fighting style that only a trained Fighter can use... and the other is some random collection of moves that anyone with a weapon in their hand can use.)
Why force the false choice? What's the up-side? You typically gain very little from one-true-wayism in a game as broad as D&D, and elegance is only a tool, not an end in and of itself.
Having fluff connecting to your character should mean something. And I don't think that occurs when one character can be a Marksman Slayer and the other is a Reaper Sharpshooter. If you look at them within the game world... there's no appreciable difference. Which I just think is rather ugly design.
Being a marksman and being a slayer aren't mutually exclusive, though. "I'm a warrior who kills monsters with my arrows!" Similarly reaper and sharpshooter: "My strength is such that I can pull this heavy bowstring and launch arrows the size of small ballisatae bolts!"
I buy that the specialties need a better grounding in the fiction to make this distinction more clear and meaningful, and it sounds a bit like the super-feats we're getting might cover that.
And the same holds true for the Three Faces Of Vampire. If you have a feat that makes you a Vampire... then are you less of a Vampire than someone who has the class of Vampire? Since you have less Vampire abilities, shouldn't you be a Lesser Vampire? And if Vampire can also be a race... then how come we no longer have the Dwarf or Elf class anymore? Shouldn't that be the case, if you can have a race and a class be the exact same thing? If we have a Vampire that can be a race or a class... then we should have the Human as a race and a class too, right? I don't see any real difference there.
All lemonade is local. Each of these questions will be answered by the individuals who have cause to ask them as they create their characters. The game doesn't need to lay down the law about it.
For the vampire specifically, I understood it as "My people are vampires" (Vryloka), "I'm a bit vampiric" (feats) and "I've decided to focus on my vampire abilities" (class), but the flexibility of these things is a great asset.
I can understand why it doesn't matter to some people, like yourself. That kind of... disconnect... probably only affects certain types of people (like myself). But I can't help it. When I see the word 'Wizard' in the game... I like that it means only one thing. When I see the word 'Stealth' in the game... I like that it means only one thing. When I see the word 'Dimension Door' in the game... I like that it means only one thing. It's clear. It's understandable. It gives me a direct visualization into what we're all talking about.
This is just getting hung up on terminology, here.

But that doesn't happen when you say the word 'Gladiator' in the game... and we have no idea if you mean a class or a background or a specialty or just a random term we throw out onto an NPC because in the story he's a slave who fights in an arena. It's a Fluff term used to describe something that doesn't necessarily ADD to the fluff of who your character is. Not when there are another four to six OTHER fluff terms already layered upon your character based upon race, sub-race, class, sub-class, background, and/or specialty.
Whenever you describe someone in the fluff at your table as a gladiator, it should mean something in the story of the game, and the mechanics of the character should line up with that story.
If, on his character sheet, it says "Ranger," and he was an enslaved ranger who fights in an arena, and maybe has a "Gladiator Training" background...what's the problem?