The outcome of the Klingon-Cardassian war does not speak to the relative strength of the Galor vs. other vessles.
The ONLY time we see non-Dominion upgraded Galors fighting is in The Way of the Warrior
The Prakesh is disabled and destroyed by the all to common(and dishonnorable) Klingon swarm tactics using superior numbers.
If a BOP is the equivalent of a heavy scout or destroyer and the average Galor is either a destroyer or light cruiser class then you can't really say it was a trial of fire between equals. It was yet another 3:1 engagement the Klingons always bring.