: I don't believe cruisers came into their modern definition determined by size
: until the late 19th century. Prior to then, a cruiser would denote its
: capabilities rather than its displacement relative to other vessels. In
: that sense you could have a frigate be a cruiser in role whereas the
: ships-of-the-line would become the predecessor of cruisers with
: fuel-powered propulsion and armored or protected hulls.

: Light cruiser is a strange term, yeah, but an accurate one nevertheless. Its
: likely role within Covenant naval doctrine would support the antiquated
: definition of a cruiser rather than the modern practice observed by the
: UNSC Navy and even the Covenant themselves with the CCS, RCS, and
: Reverence classes.

The problem with that is that the UNSC obviously still uses the same conventional nomenclature as current navies do today, and the UNSC Navy are apparently the ones that gave them these designations. All the UNSC ships appear to fit this system. We have the small frigates, the similarly-sized but more powerful and heavily armored destroyers, the large and powerful cruisers, and a "light battleship" that's despite having a similar overall length to the typical UNSC cruiser is likely far more massive, heavily armored, and packing more firepower (some of the smaller battleships of the U.S. Navy were similar in length to the average cruiser, but with more armor and thus greater displacement, and bigger guns to boot). Similarly, the Covenant has the larger CCS- and RCS-class cruisers and the much smaller SDV-class corvette. The itty bitty CRS-class (smaller than even a UNSC frigate) is when put in relation to other Covie vessels little more than a patrol vessel.

: On another note, I think the example provided by the upscaled CSO-class
: supercarrier may indicate something interesting. I find it unlikely that
: the Covenant would see fit to maintain a fleet of overwhelmingly large
: CSO's prior to the beginning of the Great War as the smaller CAS was just
: as capable. It is likely that CSO was derived from CAS instead of vise
: versa and I would suggest that CRS and CCS are much the same. Why would
: you scale down a design that you already see as effective? What works well
: with a large warship does not translate well to the roles you need to fill
: for a smaller hull. It would only make sense that CCS was upscaled from
: CRS, then a much older vessel from a time when it was at the forefront of
: the Covenant's fledgling interstellar navy, and thus defining cruisers by
: role and not size.

I think the CSO-class supercarrier is a unique vessel designed for a very specific task: a massive reconnaissance mission/sneak attack on what the Covenant thought was our homeworld. They needed boots on the ground right at the outset in order to take out key installations, secure artifact sites, etc., and to do that they needed to get past Reach's defenses unnoticed and deploy a massive force (the Long Night of Solace had a cloaking device and enough capacity to carry several corvettes in its docking bay). We know that they were attempting to disable all communications and orbital defenses as well as try to acquire "artifacts of value to their religion," to quote Halsey. While it's atypical for the Covenant to be all stealthy with a planetary invasion, maybe they felt (rightly so) that Reach would be more heavily guarded. The mission also had an obviously religious function to it, being led by a team of Zealots.