Because of its unusual position in the role-playing game ecosystem, D&D has--to a greater extent than other games--created a phenomenon where many people playing the same edition of the game are not actually playing the same game in a very real way.
There are many different ways to play 5e D&D, some of which hearken to prior editions, and some of which are probably new to this edition. I think it is important to recognize this and respect the right of others to appreciate the D&D books in different ways than we ourselves do.
Because of this, I think it behooves us as players, and those who control the D&D IP as stewards of these rules and settings, to understand when our actions may take from others the ability to have the 5e D&D experience that they enjoy having. If a change would result in that, I think it needs to be very seriously examined whether that change is in fact the best direction to take if we want to remain inclusive with the game.
Here's what's going on in this particular situation, as I understand it.
For many of us, we want the system to work for us rather than get in our way. The more efficient and streamlined at getting us the material and features we need when we need them it is, the better. (I actually count myself in that category, though it may not be apparent since I have a different concern on this particular issue.)
For many people, the game we are playing is a game where internal world continuity is a core trait. For some of us, that includes things like character classes and some features having actual in-world existence. For instance, in some of our games, "fireball is a 3rd-level spell" is an in-character statement. Wizards gaining access to spell slots and the ability to cast certain levels of spells a certain number of times, etc, are in-world experiences common to any wizard, whether they are played by the DM or one of the other players in the group. That's part of the 5e D&D game that we play.
In OD&D, BECMI, 1e AD&D, 2e AD&D, and 4e D&D, monsters have been designed to be mechanically differently than PCs. They have simplified statblocks and don't possess every feature, to make them easier to run in combat and avoid spending space on things that aren't going to be needed very often.
In 3e D&D (especially 3.5), monsters have been built to function mechanically exactly like PCs. This allows for a certain degree of precision in monster and setting design, and more easily supports an internal world continuity, but comes at the expense of making monsters much more work to use.
In OD&D, BECMI, 1e AD&D, 2e AD&D, and 3e D&D, NPCs have have been designed to function mechanically exactly like PCs. This allows NPCs to function as allies in battle, or provide spellcasting and other services that PCs can effectively anticipate based on their understanding of what level of training is required to acquire certain known class-based capabilities, supporting internal world continuity to a very high degree of functionality.
In 4e D&D, NPCs have been designed to be mechanically different than PCs, exactly like monsters, and for the same reason. 4e's intended gameplay focus deemphasizes mechanical integration between PC-facing rules and the fiction in the world, and assumes the DM will narratively handle non-combat relevant NPC interactions. Running NPCs like PCs in 4e would be contrary to design intent and involve fighting what the game is telling you to do.
5e D&D managed to create a system that would allow players to approach it from different angles.
1) Like every edition except 3e, monsters aren't built the same as PCs, for the same reasons.
2) Like 4e, monsters and NPCs are built essentially the same
3) Like every edition except 4e, NPCs are designed to approximate PCs in the world, allowing them to function as allies in battle or provide predictable services
The way 5e has managed to make both #2 and #3 true, is by making NPC statblocks simplified approximations of PC classes. While there have been a small number of anomalies from the beginning (such as the priest from the MM getting a smite-like ability not available to clerics), in the main the presentation of NPC statblocks has been mechanical simplifications of the kinds of characters you would get with PC classes. You can often look at certain statblocks and see that, for example, an assassin is about a 7th-level rogue, a veteran is about a 5th-level fighter, and a berserker is about a 3rd-level barbarian. Instead of of the complex hit point conserving features that almost every class has, like Uncanny Dodge, Second Wind, or Rage, they simply give them more hit points. If one wants to convert one of those NPCs into a full-fledged PC-class character, it is actually pretty easy to do, because you can tell from their spellcasting level or features what sort of class and level treatment they should be given (for instance, the archmage represent an 18th-level wizard from the Abjuration tradition).
This is brilliant, because it preserves the benefits of both methods that have been used in the past, and it is inclusive of D&D players who prefer to play 5e games based on any of the previous methods. It's exactly the sort of design decisions that made 5e as successful as it has been.
Now that a lot of time has passed, we're seeing the thing happen that has happened to every single edition of D&D since OD&D. At some point in the edition they start making fundamental changes to the game that are offputting to those who really liked the edition when it came out. While I'm not very familiar with OD&D, and have only a passing knowledge of 1e Unearthed Arcana, 2e brought out the Player's Options books, 3.5e introduced the Tome of Battle and other innovations, and 4e changed trajectory with Essentials. There may be good reasons for doing that (or not, it's beyond the scope of my post), but there is no good reason for not being inclusive when doing it.
5e has already shown us that they can be inclusive of a wide variety of D&D-playing styles. Taking that away by unnecessarily removing support for certain playstyles is a step backward.
And it absolutely doesn't need to happen. You can easily further refine statblocks to make them more accessible, without excising their connection to the sort of internal continuity I discussed, or their ability to suggest an appropriate full-class conversion for those who want it.
Here's one way to do it. Let's take the bard.
Original Statblock
Spellcasting. The bard is a 4th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 12, +4 to hit with spell attacks). It has the following bard spells prepared:
Cantrips (at will): friends, mage hand, vicious mockery
1st level (4 slots): charm person, healing word, heroism, sleep, thunderwave
2nd level (3 slots): invisibility, shatter
Song of Rest. The bard can perform a song while taking a short rest. Any ally who hears the song regains an extra 1d6 hit points if it spends any Hit Dice to regain hit points at the end of that rest. The bard can confer this benefit on itself as well.
Taunt (2/Day). The bard can use a bonus action on its turn to target one creature within 30 feet of it. If the target can hear the bard, the target must succeed on a DC 12 Charisma saving throw or have disadvantage on ability checks, attack rolls, and saving throws until the start of the bard’s next turn.
Actions
Shortsword. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) piercing damage.
Shortbow. Ranged Weapon Attack: +4 to hit, range 80/320 ft., one target. Hit: 5 (1d6 + 2) piercing damage.
Here we have an NPC/monster statblock approximation of a 4th-level bard of the College of Lore. It knows 3 cantrips, has 4 1st-level slots, 3 2nd-level slots, its Taunt is a simplified Cutting Words, and it even knows the correct number of spells (7) (they don't always give a full allotment of known/prepared spells). They didn't list many of their skills, but they did give them their Expertise in Persuasion and Performance. It has an oddly high number of hit points, but these approximations aren't perfect.
Can we make it better? Sure!
Accessible Statblock
Spellcasting. The bard is a 4th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 12, +4 to hit with spell attacks). It has the following bard spells prepared:
Cantrips (at will): friends, mage hand
1st level (4 slots): charm person, healing word, heroism, sleep
2nd level (3 slots): invisibility, shatter
Actions
Shortsword. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) piercing damage.
Shortbow. Ranged Weapon Attack: +4 to hit, range 80/320 ft., one target. Hit: 5 (1d6 + 2) piercing damage.
Vicious Mockery (Cantrip). Range 60 ft., one target that can hear the bard. The target must succeed on a Wisdom saving throw or take 2 (1d4) psychic damage and have disadvantage on the next attack roll it makes before the end of its next turn.
Thunderwave (1st-level spell). Each creature in a 15-foot cube originating from the bard must make a Constitution saving throw. On a failed save, a creature takes 9 (2d8) thunder damage, or 13 (3d8) thunder damage if cast with a 2nd-level slot, and is pushed 10 feet away from the bard. On a successful save, the creature takes half as much damage and isn't pushed.
Bonus Actions
Taunt (2/Day). The bard can use a bonus action on its turn to target one creature within 30 feet of it. If the target can hear the bard, the target must succeed on a DC 12 Charisma saving throw or have disadvantage on ability checks, attack rolls, and saving throws until the start of the bard’s next turn.
Compared to the revised statblock WotC is presenting, this one only takes five more lines, but lets you know which attacks are spells. It also includes spell slots so that the bard can upcast their spells (and I put an upcasting option for thunderwave right in the attack). More importantly, it allows you to have all the benefits of accessibility without sacrificing the option of NPC-PC approximation necessary for some playstyles. It isn't going to be perfect for many people's personal playstyle, but it is going to be functional and effective for almost every playstyle. This kind of design lets people playing the diverse versions of 5e D&D that they choose to play all make use of the material.
Again, I think that's the important consideration here. D&D is a huge community of players of all different sorts of games now, and we need to be inclusive of those different games that are being played. This means that not everything is going to be presented perfectly for any one playstyle. But I think it's better if the 3e fans have to put a little bit of work fleshing out the 5e NPCs to their desired level of detail, and the 4e fans have to ignore a few lines of text that are extraneous to their desired level of functionality, than that one side or the other gets things perfectly tuned to them and the other side finds themselves kicked out of the books.
www.enworld.org
