5e's bounded accuracy is why you "can't" make a mechanically strong character, not the lack of choices. The rolls matter that much more than your bonuses that a character who is mechanically strong on paper can be outdone by a mechanically weak character that rolls slightly better.
Try PF2 and you'll see how mandatory balance and simplicity of play can be combined with lots of choices.
More choices could allow you to make a mechanically strong character even with bounded accuracy. You could, off the top of my head, do more with the advantage system. It's real close to being a dice pool system, so you could just give that a nudge. You could give players choices that result in "roll X times and take the best result" to make them more effective without breaking the bounds. Elven Accuracy already sets precedent for this.
You could also do more with action economy. Have choices that result in extra reactions. Have choices that give players legendary actions.
You could tinker with damage, because that's not constrained by bounded accuracy. Give more options to change damage types, to exploit weaknesses, or just "reroll and take better"
Just off the top of my head. There's a lot of ways to increase character power and competence without giving bigger bonuses to the d20 check.
However, I think they want to keep the game very simple because a lot of players aren't, well, very good at rules.
More choices could allow you to make a mechanically strong character even with bounded accuracy.
Well, no, not really. The whole point of bounded accuracy is that it limits the bonuses you add to dice (all dice, so yes damage is constrained by it) so the rolls matter more, and choices that allow you to gain advantage, change damage types, exploit weaknesses, even reroll low damage are all included already. What you mean is that more powerful choices would allow you to make mechanically stronger characters, which is just a tautology - the reason for the limitations on the choices is bounded accuracy, so new choices that were added would still be limited by it.
That's not what bounded accuracy is. Bounded accuracy is only the rule (guideline, really) that you'll never add more than a fixed value (+20, I think) to a d20 roll. It is not about damage, HP, or how many d20s you roll.
HP and damage are free to scale, but the d20 modifiers are not.
https://www.dandwiki.com/wiki/Understanding_Bounded_Accuracy_(5e_Guideline) is a good summary. The developer's own words section is also detailed.
Ok, yeah, I guess its not the point, but as your article notes among all the things it isn't intended to do, it has the same effect. It's still what limits the effects of choices, rather than the number of them.
It limits some choices. It limits things that give you a bonus to your d20 roll. There's nothing about it that prevents other vertical growth or any horizontal growth.
You could give players a special feat every level, for example, chosen from stuff that's like "Roll deception vs their passive wisdom. If you succeed, their dexterity becomes the lower of 8 and the current value, and they are vulnerable to sneak attack."
Nothing about bounded accuracy prevents that. The fact that you don't get to pick stuff like that very often is the limiting factor on making powerful, differentiated, characters.
5e's bounded accuracy is why you "can't" make a mechanically strong character, not the lack of choices. The rolls matter that much more than your bonuses that a character who is mechanically strong on paper can be outdone by a mechanically weak character that rolls slightly better.
Try PF2 and you'll see how mandatory balance and simplicity of play can be combined with lots of choices.
More choices could allow you to make a mechanically strong character even with bounded accuracy. You could, off the top of my head, do more with the advantage system. It's real close to being a dice pool system, so you could just give that a nudge. You could give players choices that result in "roll X times and take the best result" to make them more effective without breaking the bounds. Elven Accuracy already sets precedent for this.
You could also do more with action economy. Have choices that result in extra reactions. Have choices that give players legendary actions.
You could tinker with damage, because that's not constrained by bounded accuracy. Give more options to change damage types, to exploit weaknesses, or just "reroll and take better"
Just off the top of my head. There's a lot of ways to increase character power and competence without giving bigger bonuses to the d20 check.
However, I think they want to keep the game very simple because a lot of players aren't, well, very good at rules.
Well, no, not really. The whole point of bounded accuracy is that it limits the bonuses you add to dice (all dice, so yes damage is constrained by it) so the rolls matter more, and choices that allow you to gain advantage, change damage types, exploit weaknesses, even reroll low damage are all included already. What you mean is that more powerful choices would allow you to make mechanically stronger characters, which is just a tautology - the reason for the limitations on the choices is bounded accuracy, so new choices that were added would still be limited by it.
That's not what bounded accuracy is. Bounded accuracy is only the rule (guideline, really) that you'll never add more than a fixed value (+20, I think) to a d20 roll. It is not about damage, HP, or how many d20s you roll.
HP and damage are free to scale, but the d20 modifiers are not.
https://www.dandwiki.com/wiki/Understanding_Bounded_Accuracy_(5e_Guideline) is a good summary. The developer's own words section is also detailed.
Ok, yeah, I guess its not the point, but as your article notes among all the things it isn't intended to do, it has the same effect. It's still what limits the effects of choices, rather than the number of them.
It limits some choices. It limits things that give you a bonus to your d20 roll. There's nothing about it that prevents other vertical growth or any horizontal growth.
You could give players a special feat every level, for example, chosen from stuff that's like "Roll deception vs their passive wisdom. If you succeed, their dexterity becomes the lower of 8 and the current value, and they are vulnerable to sneak attack."
Nothing about bounded accuracy prevents that. The fact that you don't get to pick stuff like that very often is the limiting factor on making powerful, differentiated, characters.