Crawford says it’s the biggest yet, with 7 classes (Experts: Ranger, Rogue, Bard; Priests: Cleric, Paladin, and Druid; and Monk confirmed), spells and weapon mastery tweaks, capstones back at lvl20 (epic boons will be pushed to another UA), and subclass progression reverted to the 2014 cadence after lvl3. Notably, rogues are seemingly getting another feature at lvl5 to make up for the fact that they get very nothing from their subclass between 3 and 9.
Subclasses in 5e functionally replaced 3.5 prestige classes. They specialize a character with specific skillsets beyond those of the core class. Instead of needing certain skill/feat/etc requisites you just get one upon reaching a certain level in the class, which is in line with 5e being (in simple terms) “like 3.5 but streamlined and more new-user friendly.”
Not really. They even tried prestige classes in 5e in an old Unearthed Arcana, and the homebrew community has taken that and turned out some good stuff with it. Unfortunately that particular UA didn’t review well, and WotC as usual threw the baby out with the bathwater and decided it meant that prestige classes are a dud of an idea entirely.
Prestige Classes in 5e could be more like (non-multiclass) Archetypes in Pathfinder 2e. They’re extra things that you tack on to your character to specialise in an unusual area that isn’t related to your core class’s competency. It’s about broadening what you can do, rather than deepening it in the way a lot of subclasses do.
That’s because they were.
With subclasses, prestige classes become redundant on top of fighting for levels you need to unlock higher level abilities.
If you want things like prestige classes and multiclassing to not fight single-class characters at the design level you need to push single-class abilities away from the high levels of the class, which just leaves them empty and boring. At which point, why bother playing at high levels? Why bother single-classing ever?
You just end up removing choice by turning what should be a valid decision into a false-choice that does nothing but penalize you.
3rd edition, for example, should have cut the base classes off at level 5 or 10. The way the game was designed, there was no need for them past that point since everyone ended up taking either alternative base-class levels or prestige class levels.
With subclasses, you either need to embrace dipping and only define the base classes to level 15, getting rid of EVERYTHING that comes out in levels 16-20 (which kills a sacred cow and will make some people, like me, very un-happy), or you need to retire multiclassing, or at least try to balance it.
That means no more subclassing at 1st level and, preferably, standardizing subclass ability levels. Why people are against that I have no idea. Who cares if everyone gets their 2nd subclass ability at level 7 regardless of class?
Honestly, the only reason I can think of to want them at different levels is purely for power-gaming. The ability to plan out “a build” that is hands-down better than other builds because you get to squeeze in one more ability than other builds.
Seriously, what are the other reasons? The valid reasons?
Of course not. Prestige classes don’t do the same thing that subclasses do. They aren’t a specialisation of the abilities within a class, they’re a broadening to a set of features that could theoretically be taken by characters of any class, but which is not in depth enough to justify being its own full class.
But talking about things in the abstract is pointless. I’d rather point to actual concrete examples. Because the 5e homebrew community has shown categorically that there is a useful place for Prestige Classes. This vampire prestige class is the one that most convinced me of it, but you can find a whole heap of good examples of prestige classes in the homebrew community. Sure, you could design a full 20 level vampire class (and 4th edition did!), but it really works better if you have a highly flavourful and more succinct series of abilities. Get in, give you the abilities that satisfy the fantasy, and finish there. But to make vampirism a subclass doesn’t make sense. Which class would it be? Rogue? What if you want to be a wizard who gets bitten by a vampire? Do you now have to multiclass into rogue, and only get vampire features once you reach the 3rd level of the multiclass? And not until the 9th level before you get more vampire stuff? That’s just this one vampire prestige class, but any time you have a concept where that same reasoning could apply, that’s an example of a concept for which the prestige class makes sense.