Abstruse said:
But what makes the ranger with the hunter theme different from the ranger with the archer theme or the tempest theme or animal trainer theme? What makes the different rangers unique from one another? If all rangers look exactly alike, why should it be a class instead of just a build?
I can answer that with a bit of a digression.
In 4e, you have (at least) three different ways to do a Vampire. They are not mutually exclusive, so you can have a character that does ALL THREE THINGS, if you want.
I've played a character that does that. So I speak from experience in this regard.
They all get iconic vampire powers. Blood sucking, energy drain, turning into bats and wolves, turning into a cloud, etc. They sometimes do it in slightly different ways, at slightly different levels, and with slightly different mechanics (as befits their different design holes).
What is the difference between
Form of the Bat from being a vampire and
Crimson Wings from being a Vryloka? (DDI Links) Honestly, not much. And those are
in the same book!
So what would the difference between "I'm a ranger and I have two swords!" and "I'm a tempest and I have two swords" be? Probably not much.
This is a
good thing, because as much as I am a weirdo and like creating Things That Were Not Meant To Be and then playing them as characters, most people probably aren't. They're going to find the one way that they want to be a vampire, or wield two swords, and use that. And if they somehow decide to be BOTH a tempest and a ranger? Well, then they've spent their limited character creation resources on being able to basically pick whichever of the two "I use two swords" abilities they like the best, since it doesn't magically give you more arms.

Much like Kiki the Vampire Cheerleader was able to choose between two different ways to turn into a bat (she went with the Vampire ability: she favored the extra speed over the extra defenses, and I've got a philosophical problem with all of the "when your flying ends you descend safely" insanity.

).
These are all Good Things. Choice. Versatility. Flexibility. Modularity. Now if I decide my campiagn world resembles
Coruscant - Wookieepedia, the Star Wars Wiki and I ban rangers, I don't also have to ban TWF. Or if I decide that I have an arbitrary problem with TWF ("NO DRIZZIT CLONES EVAR!"), I can banish that without banishing the Ranger.
Crazy Jerome said:
Well, alright then. It actually needs to be different, and different enough to warrant taking up a slot. Now granted, "enough" is the largely subjective thing here, and runs into the issues of convenience, tradition, and so forth.
So if there are, for examples, classes for fighter, paladin, and cleric--and then multiclasses between them--and then perhaps some themes that poach a bit, such as maybe "cavalier" or "knight" or "templar"--there needs to be something hanging on that paladin class that works well with the central bit of the archetype (by itself or combined with some of those other things), that is "different enough" from a fighter/cleric or a guardian cleric or a templar fighter to make the paladin class not totally redundant. It doesn't need to be huge, but it needs to be there.
They don't need to be very different at all. Blood Drinker from being a vampire and Blood Drain from having the Vampire Heritage feat (and, to a lesser degree, the Vryloka racial utility) fill identical conceptual space: they're both there so that a vampire character can drink the blood of their enemies and gain power from it. They're three solutions to the same problem, but they're all subtly different, because they fit in different design spaces and had different designers and produced different results. Kiki's got at LEAST three different ways to drink someone's blood. Which is great. She's REALLY vampiric. She should be, with as many vampire options as she has.
I'd imagine many TWF abilities looking pretty fundamentally similar (though we've seen solutions that range from "you just get another attack" to "use a power or nothing special happens"), but you could look at, say, the ability to cast some nature magic, in a LOT of different ways. Do they just get some rituals? Do you let them cast druid spells? What about the Nature domain? Well, we don't have to choose just one. We can use whichever one feels right for the design space we have for it. And some character who REALLY wants to cast nature magic might do all of 'em.
A highly modular game doesn't need (or benefit from) niche protection. Wanna make a Paladin with a Knight background and a Cavalier theme and also multiclass as a Fighter and a Cleric? Congrats, you're the 5e version of Kiki.

It's not a problem. It IS kind of a monodimensional character, but heck, if that's what you want to play, go for it.