Bigger doesn't mean better, just different, you're right. All the talk of dreadnoughts in and out of the novels, and what I see is that you'd have Garth of Izar in command of one in the 23rd century and Jellicoe in command of one in the 24th, because those guys meant business. I have no idea if Garth did anything but fight, and Jellicoe (the only human besides Barclay that I like in century 24) is the anti-Picard in so many ways that he absolutely deserves a dreadnought.
I'd like to hear more about your opinions concerning 24th century humans, but this is obviously the wrong forum. Personally, I both respect Jellico and admire Picard.