Timeline: Enterprise B/C era & Cardassian War

[Dukhat]

Regardless, I'm staying with the version that O'Brien was in the ground action in 2347.

That is your choice.

There's that, and the fact that he became a transporter tech / engineer after, in the thick of battle with Cardassian forces, he figured out how to fix the transporter to save his squad.

Yep, that info coincides with the "Realm of Fear" statement, since he states that he didn't know a 'transporter from a turbolift in those days,' implying that this was the first time he used one. However, it also states that because of this, he got promoted to tactical officer and got a 'gold suit.' If this happened in 2347, O'Brien would have only been 19 years old. I simply don't see him being promoted to such a prestigious position that young, no matter what he did to save those officers. Also, when did Starfleet change their uniforms from the monster maroons to the TNG season 1 uniforms? Because getting a 'gold suit' implies that this would have happened at least before 2347 if we're going by that date.

PTSD is a funny thing. One can be triggered decades after living a perfectly normal life. He saw events unfolding just as they did in '47, and he said he could not allow it to happen again. PTSD triggered.

I'm not really buying that in this instance. I'm pretty sure that for 20 years Maxwell had to undergo lots of psychological evaluations in order to be the captain of a Starfleet vessel in all that time, both on the Rutledge and on the Phoenix. Already knowing how fragile his emotional state might become based on his experiences during the war, I don't see Starfleet allowing him to continue in command if they were concerned that he would have any kind of relapse.

But hey, then again this is the same Starfleet that let Picard continue in command after being turned into a Borg, so who knows.

 

[BrotherBenny]

2347 makes sense to me because we're basically told the 2350s was the last war decade and things had mostly calmed down by the early 2360s. The Cardassians had stopped expanding and were holding onto to existing territories, and the launch of a new Federation flagship makes everyone take a step back for a moment.

Everyone also waited to see what happened after Wolf 359, and learned the Federation was not to be trifled with. I'd also argue that O'Brien is older than Sisko. He's a Chief Petty Officer, I doubt there are any SCPO or MCPO in Starfleet so he's at the top of his field.

By 2369, the Cardassians were flexing their muscles again and this time the Federation said, here, have these planets and go away. They faced guerilla warfare by the Maquis and on Bajor, likely on their other other holdings too, and so the military chose to retreat instead of completely losing everything, aided by increased power by the civilian government.

 

[Shamrock Holmes]

Everyone also waited to see what happened after Wolf 359, and learned the Federation was not to be trifled with. I'd also argue that O'Brien is older than Sisko. He's a Chief Petty Officer, I doubt there are any SCPO or MCPO in Starfleet so he's at the top of his field.

Given that O'Brien specifically identifies himself as a "Chief Petty Officer" and "Senior Chief Specialist" in dialogue at various points, we can reasonably assert that at least the equivalent of a SCPO exists periodically in Starfleet.

 

[Sgt_G]

Star Trek as always been absolutely allergic to Enlisted troops, save for when it fit the plot. O'Brien is the lone exception, it seems.

 

[Shamrock Holmes]

And Janice Rand.

Probably Odo. Technically.

I suppose most of the Voyager Maquis being enlisted would count as "when it fits the plot".