You have to pass a Barter check or do a quest for Major Knight in order to succeed. How is this a problem?
From a quest design standpoint, it's not a problem. From a worldbuilding standpoint, quite a bit:
- You're a random civilian. Hayes, an NCR Lieutenant, telling you that it's up to you to find out what to do with Primm is ridiculous. The NCR look inert. They can't wipe out the gangsters in Primm with a whole squad, but you can do it solo. After the gangsters are wiped out, Hayes sits around waiting for
your instructions. He's a Lieutenant in the army, you are a civilian.
- Hayes has been told by the NCR that the troops simply aren't available to take Primm, despite the fact that it's said to be of value to the NCR. With one relatively easy Barter check, Major Knight can be convinced otherwise. By you, a civilian he's never seen before and who has no relation to the NCR.
So, thus far in this quest, we've met two NCR people. A Lieutenant who asks you to do his job for him, and a Major who does as he's told as long as you pass one simple speech check, the dialogue of which is you telling him something he already knows.
- After this point, you walk back to Hayes. Hayes then asks you
if it's okay with you for him to take over Primm with the new troops that you convinced Knight to send. The in-game reason for this is that it gives the player a last chance to decide to put someone else in instead... but it makes no sense. The troops are ready. Hayes has received word on the radio. Why is he waiting for your
permission??? Who are you? You're nobody, you're a postal worker who isn't in the NCR, why is Hayes asking you what to do?!
- While this is happening, everyone in Primm stands around indoors waiting for your decision. They have suggestions, but they all agree that it's up to you, someone who does not live in Primm and who they've never seen before and who has no reputation, to decide their fate, and they'll all gladly go along with whatever your call is.
- As a bonus bit of fun, you can install anyone else other than the NCR, and Hayes will sit and watch as Primm is lost before his very eyes.
Overall it just makes the NCR look comically inert, a trend they maintain for the entire game. It also establishes the Courier as the most important person around and someone who calls the shots and who NPCs will rarely object to the life-changing decisions of, a trend that also continues for the whole game.
There must have been a way to write this quest that doesn't immediately position the Courier as someone who can order NCR officers around while they sit around aimlessly waiting to be told what to do. They could at least make it so that the people of Primm have strong opinions and try to influence (or force) you one way or the other. They could at least make it so that the NCR have something to say about you walking in and telling them that you, a random stranger who's passing through, have made your decision on the future of Primm and that you expect them to follow it at once.