posted
Indeed, it seems likely (although perhaps this wasn't the intention of the writers) that Picard was only referring to the fact that the Romulans had been a no-threat from the RW to "BoT", and then a century ago in "BoT" again became a new threat. Then somebody read Kirk's report on "BoT" and said "Oh, we can handle them", meaning "they cannot escape their NZ now any more than they could before - cloaks or no cloaks, warp or no warp, Vulcan blood or no Vulcan blood; nothing has changed".
However, since by the movie era the Romulans are clearly "out of their shell", with ambassadors and agents all over the galaxy, this Somebody was wrong. Alternately, Somebody meant "let them come out, they won't bother us since we are stronger". Possibly the buddy-buddy relations with the Romulan ambassador in ST6 were part of this "we are handling them, they are domesticated now" thing. And when the Romulans later went bad and did whatever they did at Tomed, it became evident that Somebody *wasn't* "handling them" after all.
This doesn't address the "warp made them thugs" issue, though. Here, they simply became thugs when let out of their RNZ. Whether this was due to warp, or cloak, or politics, is not specified. To account for the "warp made them thugs" part, one could say that they did gain warp around "BoT". Or then one could say they gained warp in the RW era, and this war was the reason they were considered thugs.
Dunno. Probably I'm reading too much into this dialogue. IMHO it doesn't explicitly tell us anything about the timeline of Romulan warp, and a variety of interpretations are possible.