In general, the book features a few changes that are more errata and clarifications from the previous edition than anything else. The best change to this book is actually in the very first section as it addresses an RPG format philosophy that has existed in the RPG world for quite some time; the basic rules are finally in the front of the book ahead of character creation in "Chapter One: Playing the Game." For decades now, conventional wisdom in RPG publishing has dictated that a player should create a character before learning how to play the game. The idea behind this was that creating a character would prompt a player to become more personally invested in the story portion of the RPG, thus making them more enthusiastic to learn the sometimes tedious rules set.
The 2024 Player's Handbook reverses course on this notion to the one of the bygone RPG publishing eras. This book heads back to the original practical idea, set forth in classic RPGs, that players can't effectively fill out the stats on a character sheet without knowing the rules, so the core rules need to come first in the book. Neither method of formatting an RPG core book seems to be particularly superior to the other; it's all a creator's priority. However, for D&D, going back to the "old ways" makes sense as there are dozens of character subclasses, and new players sifting through those additional spell selections, feats, and abilities without knowing the basic rules would create some level of confusion. Having the rules front and center is a welcomed change.
Aside from shifting of the rules placement in the book, another great feature of this book is the some of the changes to spells and feats. At the Wednesday night D&D event at Gen Con, the design team pointed directly at clerics as being a problem in 5E because they could combo bonus actions with other actions, which would slow down combat flow significantly. Spiritual Weapon was noted specifically in this instance, and in the D&D 2024 Player's Handbook it was changed to a Concentration spell. This type of streamlining of rules occurs periodically throughout the book, and is an excellent improvement.
Other points of note in the book include crafting rules and a weapon mastery system, which had both been mentioned early on in the roll out. The classes and subclasses have been improved, and all of the character types seem to generally better versions of their 5E counterparts. One of the true highlights of the book is a fairly comprehensive rules glossary that allows players to quickly look something up without digging aimlessly through the 384-pages of the book. These improvements are all excellent bells and whistles. And of course, the interior artwork for this book is truly excellent, bringing the pages to life.
Dungeons & Dragons: 2024 Player's Handbook will officially hit the streets on September 17, 2024 (see "2024-25 Deets and Dates").