There's probably one very simple reason actually.. the Hurq' ships probably outclassed most other vessels in the region in that era, with the exception of the Vulcans, whom they couldn't, or avoided, defeating (the Vulcans being a tough nut to crack, given their huge battle cruisers, and relatively small range of operations, meaning it was not hard to call on a HUGE fleet!) Klingon ships appeared to be among the most powerful warships of that era, though of course being outnumbered 5-1 wouldn't help :D
your vision sounds pretty much what I imagined actually. The Klingons' semi feudal society points to technology being thrust on them, and where they did advance was primarily in weaoonry, hence they more or less managed to keep pace with the Federation at the expense of pretty much every other advancement :D