I'll give you an example of a RPG mechanic what could exist in the game, but wasn't.
Choice to give the player a chance to make his own "V". That's a good RPG mechanic example.
You wake up some day and suddenly think: "You know what, it's scumbag V time!"
Then you go out of V's apartment, shoot the neighborhood (Stop making noises, dammit), slap Wilson's (weapon shop vendor) face: "You always keep the shooting range closed, you dumbass, how dare you?"
Then you go out, make a police chase, end up in the desert. Stay there for 3 days, hidden, then suddenly someone calls you.
"Hey V, it's Maiko, I heard you lose it, because, you know, it was scumbag V day, bu this had a price. As you helped me in the past, pay me 20.000 eddies, so I can use some Arasaka contact to make some negotiation with NCPD. If you don't have the money, I have some work for you. Give it a thought."
If you don't accept, then after some time you receive another call.
"Hello, mr. Scumbag V, even when we can't see it, God is always looking for us, just as I'm always looking for my mercs. I heard you got problems with the law, I made some contacts with the Valentinos and they said they have a place to sell in Heywood. You can pay in cash, or get rid of the police in one of the Valentino's area, do that and your place in heaven will be secured."
If you wait a little longer...
"Hello V, it's Panam, listen, I know you messed up this time. People in the city hate your guts, because of what you have done, but you're family, even being a mr. Scumbag V, there's a tent for you here, and we could use your contacts to provide jobs to the family. Think about it."
If you don't accept it, then you could call NCPD, with a non trackable call. In the call it's given you the option to surrender yourself and get arrested, to get alternative punishment instead of prison.
"You are a scumbag, mr. Scumbag V. But as you made somenpolice work before, the judge gave you the option to pay a 15 thousand fee, or you can clean up three gang turfs, arrasting these criminals, dead or alive, it's your choice, mr. Scumbag V"
If you don't choose it, then Kerry calls you:
"Hello, mr. Scumbag pretty ass V, I knew that you blowed up, so if you want to, you can stay at my house. But keep it in order, okay? And help me to get my guitar back, please, some guy paid a fixer in Heywood to rob it from my nephew, do you believe that? The scumbag took Silverhand's shoes too! (Scumbag V: "No, never heard of it"). Anyway, call me if you're interested".
Alternatively, you could call Delamaine.
"Hello, Delamaine, it's me, Scumbag V, listen, I need a car in the desert, near the Batman's cave"
Delamaine: "Of couse mr. V, you're an excelsior client, but considering that you made my cars free, because you're a scumbag, it'll cost you 20 thousand eddies."
Or you could make a "Charity loving V".
Donating money to churches, helping children, capturing bandits.
Then, corpos call you, politics will praise you. You receive invitations to TV shows.
Corpos: "Hello, mr. Charity V, I heard of your good actions and our brand could use that to, you know, ahem, do what is right for u.. the city. If you are willing to, go to studio X, and we'll make an ad using your image to our new semi vegan bio organic carnivore food tooth paste that gives 200% of daily vitamines everytime you brush your teeth. You'll be well paid, or we'll give some calls, then you receive some great discounts on some shops"
NCPD: "Very well done citizen. You’re invited to visit our instalations, to see how we train or soldiers, and talk to our chief."
Chief of NCPD: "Hello mr. Charity V, considering the valorous work you have been putting in the city, we have a proposition to you: we have this gang problem in north of Night City, so if you choose to accept our offer, we'll give you an uniform, and you will arrest wanted people, so in that way you'll get paid, and depending on how much you work, we'll be sending some equipaments to your apartment, and the officers will be very pleased with your presence."
Then if you do some police missions, officers starts to greet you when you call them, vendors will give you a discount, people will call for your help and so on.
Not only the RPG mechanic of choice is lacking, but making those choices meaningful, make the world react to them.
That's why even cursed with "Bethesda charm", Fallout NV (rushed by Bethesda) is so praised.
