...If we want to shoehorn "Balance of Terror" into all this (and the episode is a poor fit even within the TOS continuity, where all other episodes discuss invisibility as an old and common trick), we can always point out that the cloaked attack in that episode seemed to be the brainchild of "the Praetor". Given that Praetors in the Roman society were many, and always backstabbing each other and vying for power via pet projects that often were wars, it would make quite a bit of sense that the "Balance of Terror" attack would be something not particularly condoned by the Star Empire at large, or at least something not openly being prepared as of 2258 yet.
Peace initiatives sound good, IMHO. Between the divergence point in 2233, and Nero's attack in 2258, Starfleet in the STXI universe apparently learned a lot of facts about the Romulans, while Starfleet in the TOS universe learned nothing. How does one learn about the Romulans? By having them agree to contact. And that contact would be either war, or then a peace initiative. There's no clear indication that there'd have been a war in the recent past, so perhaps the Romulans came out of their shell in order to wage (insincere) peace?
Interestingly, we never learned what it was that kept most of Starfleet at the Laurentian system. It didn't relate to Nero's attack on Vulcan because those ships were at Laurentian before the Academy got the news of that attack. But it could have related to, say, an unidentifed Romulan's (that is, Nero's) fight with the Klingons (revealed the previous night, as Uhura tells), or anomalies in the Neutral Zone (also revealed recently, as Chekov says). If Starfleet was that concerned about vague things related to the Romulans or the RNZ, then it's quite possible that there indeed was a war with the Romulans at some point between 2233 and 2258! Or at least a raid similar to that described in "Balance of Terror".
Also,
This is diverged from the ENT timeline, remember? The Romulans have had cloaking tech for a hundred years by the time Nero first arrives.
For all we know, they had that tech for a hundred years before "Balance of Terror", too - they just didn't reveal it to outsiders in that timeline.
Or perhaps Archer's Starfleet didn't reveal the existence of Romulan invisibility devices to Kirk's Starfleet, for whatever reason? Plenty of dramatically interesting reasons could be woven into the fabric of the Romulan War that separated those two Starfleets...
Timo Saloniemi
