2. Bounded accuracy is great for combat, but I'm less happy about its effect on skills. Combat involves a heap of attack rolls; even a modest difference in AC or attack bonus will have a significant effect over the course of a fight. Skill rolls tend to be one-offs, and the randomness of the d20 overwhelms the skill bonus until you get to fairly high levels.
4. While 5E does multiclassing better than any previous edition, it has not managed to avoid the "first-level problem." Due mainly to proficiencies, your class selection at level 1 has a significant impact on the viability of your character. A level 1 fighter/level 1 wizard is much more powerful than a level 1 wizard/level 1 fighter.
6. The DMG guidelines for calculating CR have some circular logic going on. The monster's attack bonus is one of the things that factors into calculating its CR, but CR determines proficiency modifier, and proficiency modifier plus ability mod is what determines attack bonus. I feel like the 5E CR guidelines are trying to meld the 3E "assemble the pieces" system with the 4E "modify a template" system, and the mixture didn't quite gel.