I like to think in terms of weapon systems: somebody at Starfleet probably went "Now what will it take to field the Mk 26 Quadruple Photon Torpedo Launch System and nothing extra
?", as opposed to equipping a large and complex light cruiser with Mk 26 in addition to all the sensors and shuttlebays and laboratories and whatnot. And the answer turned out to be "A ship half the size of Miranda
That way, we don't have to search in vain for all the usual starship features in this model; it's not necessarily a 1:1 successor to some preceding type, but more like a 0.25:1 addition to Starfleet's arsenal in the early 24th century.