I don't think a passive blanketed increase in turn rate for all cruisers or even some cruisers is needed or warranted.
I see two arguments supporting an increase of cruiser turn rate. Please note that my wording of these two arguments is intended to "sum up" various things I've read, and so may not contain or represent an opinion in whole; however, it should point toward the original intent.
1: The current rate of turning is not fun.
2: The current rate of turning is too limiting in X situation.
While argument 1 shouldn't be wholly disregarded, this argument is fully subjective. Taken to an extreme, if the cruiser had an infinite turn rate and just automatically and instantaneously aligned its optimal firing vector to its target, this could still be considered "un-fun". The problem here is in the lack of definition for such a subjective term. I do not wish to dismiss any argument that flying a slow ship can make things less fun or even make them tedious, I just wish to display that using a term as a grounds for argument isn't very useful.
In argument 2 is where most of the actual problems with cruisers may lie. It can be argued that the situations in which the turn rate limits the performance of the cruiser are there by design and constitute the weakness of the cruiser. This, in part, happens to be my own opinion. It also could be said that the captain of a cruiser is not given enough tools to avoid these situations. It follows, then, that the solution for this argument may not be to make cruisers turn slightly faster, as a small increase may just prove disappointing in this regard, but instead to provide captains with more tools to maneuver.
I find it interesting that scenes from the TV show have been cited in this thread. I would like to submit that in non-combat cases, i.e. quickly turning around to go to warp, or any maneuver under normal conditions, the ship would not be powering weapons and shields, and would likely be devoting its power resources into its engines and other systems in such a way that a maneuver could be made. It is perfectly reasonable that in a combat situation the ship would have to give its power to weapons and shields, and be unable to make this maneuver. This is what power allocation within the game seeks to emulate.
I would also like to note that a single instance of a maneuver within the TV show does not imply a passive ability to perform such a maneuver under any conditions. If the Enterprise-D was able to turn quickly in one situation, that does not mean that it can fly circles for days on end around a pin. This is what situational powers in game seek to emulate. In the case you do need to turn around quickly, such abilities and techniques exist, although possibly not prominently enough.
Solutions to this issue I think come best in this way: increased ability to maneuver at a cost. If we agree that the primary advantage of a cruiser is defense, while the primary disadvantage of a cruiser is maneuverability, we could illustrate this with a continuum, where escorts lie further toward maneuverability and cruisers lie further toward defense. If a captain wishes to place his ship somewhere between these two points, he can give up some defense for maneuverability. This can come in several ways, but simple solutions are desirable.
One simple way is to remake the RCS consoles, possibly in the way previously suggested, so that the captain of a cruiser could use an engineering console slot to increase maneuverability, which otherwise could be used for increased defense. It seems fitting that this may have been the intent of the RCS console from the beginning. Unfortunately, the console is ineffective, and so the problem lies in implementation, not necessarily in concept.
A less simple solution, which could supplement the first, could be to increase the benefit of engine power on maneuverability. This refers to previously mentioned TV show scenes, where I hoped to presume the thing responsible for turning ability could just be allocation of power and resources. If a captain so wished, he could directly give up weapon or shield power for maneuverability. This could lead to some interesting gameplay across the board as power management becomes more dynamic.
To conclude, I would like to say that my own view on this subject somewhat contradicts everything I just wrote. I'd be quite happy to see cruisers left the way they are right now, as it takes some measure of skill to get from place to place in an efficient manner. I do, however, acknowledge that sometimes the time it takes to turn can be very limiting. To answer this I have an escort ship that I use for dailies and much of solo play as it simply makes things go faster. I do not, however, enjoy the gameplay nearly as much as when I use my cruiser in group play. Someone mentioned earlier that very few people have said they love how cruisers play currently. I'll add my own name to these very few. I really like how my ship that has 4.5 million metric tons of mass "feels" thus. The defiant seems like a toy airplane to me. I want the biggest, slowest, clunkiest, sit-at-range-and-fire-the-long-guns-iest ship there is. I want to fly a fortress that sits in the middle of a maelstrom impregnable and stalwart. And that's what I do.