This all sounds like changes made in order to answer the unwashed masses' question "which class is the best?"
The idea was to make every character equally capable in combat and in non-combat encounters, rather than for example having the rogue be the king of skills and non-combat encounters, the fighter great at combat at low levels and shit later, and the wizard, the opposite. Also, they tried to make every character have interesting mechanical decisions in combat, rather than the casters having a huge list of options while melee guys only have "I attack". Those are not bad goals for a game where the rules, the design, and the gameplay expect that there's going to be combat regularly. But the execution was too constricting for those who follow the RAW.
It was worse than this. They basically killed vancian casting, split abilities and spells into at will, encounter, short rest and long rest version. Many abilities between classes were same but would attack different enemy defense. Most did same damage at same levels no matter the class it used them. They would just be given a different name and a minor mechanical difference. Also those abilities had very strict number definition, almost no descriptive text and were basically unusable outside combat without lots of house ruling.
Monsters were just as bad or worse. They were turned into short stat blocks for combat with almost nothing beyond that.
Vancian casting, while many have come to embrace it as default, is not really that great and not simulationist at all. It makes no sense that you'd forget a spell after it is cast, except in Vance's world. 3E was already experimenting a lot on how to go beyond that system, with many classes having alternate spell casting systems (sorcerer, warlock, psionics), and 3.5E diminishing the restrictive vancian scheme of the wizard where you had to know exactly what you'd need for the day when you woke up and couldn't change what you have memorized during the day.
But it is true that the strict separation in 4E between combat abilities and non-combat ones was problematic. People expect to use their powers/spells ouside of combat to solve problems, but the system didn't explicitly allow for that. You needed a good GM to bridge that gap.
In the case of monsters though, I have no problem with the combat stat blocks, they made combat fun and dynamic, easy to reference and concise yet the powers they had were impactful on the battlefield. You just had to change mindset, where the stat block is not everything that a monster/NPC is and can do, but is rather just a shorthand for what he will do
in this combat encounter. That's very unlike 3E, where a "stat block" told you everything about a dude, rather than what he'll do now. In that respect 3e was very simulationist, while 4e is gamist in its approach. So in 4E if you wanted to use the monsters/NPCs outside of combat, you'd design an entirely different thing, focus on the skills they have, list motivations and goals, maybe build a negotiation challenge if you're into that mechanic. In my campaign, I had recurring NPCs which used different powers in different combat encounters (aka a partially different stat block), depending on what they were trying to do. 4E was flexible enough to do that, and the mechanics were easily manipulable that if you needed to add an ability or power during an encounter, it was very easy to do. The designers did the same in the published adventures, the same NPCs having different stat blocks at different moments, or a list of motivations etc. for non-combat encounters. But I guess the gamist approach, which was great for a GM, didn't work that well when people took it as a simulationist account of all that a monster/character is.