I think something that people unfamiliar with 5e aren't grasping, is that limitations on action economy are what give certain classes and subclasses their identity.
In 5e, every class has the ability to use their action to disengage, hide, dodge, and dash as an action. This represents taking the majority of your 6 seconds in a round to utilize it in a way that is situationally greater than simply attacking or casting at you foe.
Certain classes are so adept at maneuvering or sneaking that through their class features, they gain the ability to use some of them as bonus actions instead. These classes include rogues, monks, and to a lesser extent; rangers and eagle barbarians. The ability to use these actions as bonus actions gives these classes an edge that really makes them feel like they are a step faster than their other party members and solidifies their character identity.
That doesn't mean that other classes don't have things to bring to the table with their bonus actions. While the speedsters have an edge on the maneuverability side; Barbarians, fighters, and paladins may be using their bonus actions to attack with reckless rage, smite effects, or GWM/PAM. These heavy hitters came to brawl, and they're gonna use their bonus actions to bring the pain.
Well what about casters? What do they get? Casters get a spellbook full of spells to play with. Clerics have more bonus action spells than you could ever ask for. Sorcerers can spend sorcery points to turn action cost spells into bonus actions instead. Bards have inspiration for their bonus actions and can choose a couple spells from other classes if they want even more to do with their bonus actions. Druids have wild shape and again... spells. Warlocks... rangers... paladins... spells.
As a character levels up, they gain access to more and more possibilities as to what they can do in their turn. So most classes already have options to look to for their bonus actions. One's that don't can generally take a feat to give them more freedom in their bonus actions. There's also the ability to duel wield to get bonus action attacks.
The problem with diluting the distinction in action economy is that it kills variety and destroys class identity. Arcane tricksters barely feel more roguelike than a Wizard that took the criminal background, due to the Cunning Action handout. What's the point of taking the shield master feat, when everyone got the most important part of it for free? Why would I ever want to play an Eldritch Knight, when anyone can replicate their iconic 7th and 18th Level War magic feature by dual wielding? Why would I pick a control caster and pick spells that give my party members advantage on attacks when advantage comes freely. The list goes on.
Having options is fun, which is why you pick classes that have the options you want, because those options make you feel like you are that class. If everyone is special, then no one is.
Thank you for this post, it's brilliant. You've managed to put into words my frustrations; Larian really should be taking on board your feedback here. Sometimes it feels that Larian are struggling to get a handle on how to implement DnD effectively.
