The Demon is one of the most iconic FreeSpace designs. It seems rather straightforward and stereotyped in the way it looks but it features most, if not all, of the peculiar Shivan characteristics.
When you mentioned that the Demon has "most, if not all, Shivan design characteristics," I immediately thought, "wait, the Demon is a symmetrical ship and the Shivans have a penchant for asymmetrical designs," after which I realized that most Shivan ships, with noteworthy exceptions like the Nephilim bomber and the Ravana destroyer, are in fact symmetrical.
Also, great job for giving its fighterbay the importance it deserves. The Demon probably wasn't an assault destroyer just like the Ravana was, but it definitely had some more carrier-like capacities. No convoy would be safe in a star system with one or two Demons roaming around.[/color]
I remember the Blue Planet tech descriptions specifically describing the Ravana as a "strike destroyer" and the Demon as a "line destroyer," and those particular terms seem quite apt to me. I'm playing through Act 2 of Derelict right now where the Nyarlathotep is indeed accompanied by both a Ravana and a Demon and I was reminded of the different, but still devastating, roles of both destroyers. In FS1, having both the Lucifer and the Demon-class Eva in the same system was a big Oh Crap! moment for the Terrans and Vasudans; having those two
and a Ravana in one place? "Yeah, we're screwed."