The implication of the Defiant is what I find somewhat intriguing. It appears to have tactical capabilities in the ballpark of a Galaxy-class ship like the Enterprise D, at like a 1/10 of the size. So what does that imply? It implies that the Enterprise is 10% tactical, 90% other (science, humanitarian, diplomatic), which seems in-line with Starfleet’s mission. So, the Defiant is Starfleet’s first warship not in the sense of what it has that the other frontline ships don’t, it’s what it doesn’t have compared to the other ships (the non-tactical 90%). Yet, the Enterprise is considered a match for frontline warships of the other major powers. So, the conclusion is that the Federation is incredibly more advanced than the other powers, when it comes to tactical and technical effectiveness. They pack into 10% what the other powers need 100% to do the same job. All of this is, of course, subject to the “they’re as weak or as strong as they need to be” rule.