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.
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?