Okay, so Real Life(TM) has intervened for a while, but I've finally got some work done on a few profiles again. Starting with this beauty: soon to be featured in the independent fan film (lawsuits pending) Star Trek: Axanar, the USS Ares.
In the short Prelude to Axanar, the Ares was identified as Garth of Izar's ship during the second half of the Four Years' War, the only 'hot' conflict between the Federation and the Klingons in the 23rd Century. Axanar Productions have moved the timescale slightly, shifting the war to the 2240s rather than the 2250s favoured in the original FASA game book. This would mean that the Ares-class was likely to come on-stream in about 2244 and first saw action at the Battle of Cygnus III.
In my mind, the Ares-class was under development for some time before the war, probably as a patrol ship to free up larger vessels for exploration duties. The outbreak of war would've seen the design outfitted with more phasers and torpedo tubes to create a pure warship for the only time in Starfleet's history until the Defiant-class started development in 2365. The Ares would have gone straight into production without the prototype stage, hence her being rated as NCC instead of NX-1650 when launched.