Classes
Without dissecting the ins and outs of each class, I want to describe the classes that are and are not included in the edition.
They have removed five of the starting classes from 3rd edition: Bard, Barbarian, Druid, Monk, and Sorcerer. Those have been replaced by the Warlord and Warlock.
Why remove those classes. I can understand the Warlock replacing the Sorcerer. That is not to say I like one or the other better, only that they could have many reasons to replace one type of arcane spellcaster with another. Removing the monk and barbarian is odd, but understandable. They are martial classes where the fighter, paladin, and ranger still exist. The new Warlord, which is an odd choice for a starter class, is a martial class to act as a sort of replacement.
That leaves the removal of the bard and druid. These have been staples of D&D for a long time. I see no point to their removal. It does not add anything to the game; and how could it since they didn't replace them with anything. Even if they had, it would have been a negative since these classes are iconic in D&D. This decision is the worst I have come across in the new edition to date and is worse than any chance that was made going from 2nd to 3rd edition.