Yeah, I'm with you. The domey ones are the good ones.Showing my age in saying this I guess, but the domey ones are the most Comety Comets, to me. There weren't flat Comets, until the second LE run of ESP Comets, and even then they were an anomaly. These days, they're the rule, rather than the exception...
You're right, though. The extra HSS in the domey ones does tend to lend to better low-lines, because you don't need the added height to account for how much more flippy the flat ones are, as well as the decrease in glide compared to the domey ones.
I will say, the flat ones have gotten more stable over the years. My Icon MJ ESP one is a lot more stable than the max weight flat LE ESP ones back in the day, so is the Cryztal Sparkle one I've got.
Right around the time of the 2nd run LE's the X Comets were flat as well; I made enemies at Marshall Street complaining about flat X Comets I got in an order. The general talk amongst the Comet folks at the time was that these were squirrelly with less glide and to avoid them. I remember specifically talking to Blake complaining that I was pretty sure I was using the same motion and getting inconsistent results from the flat X Comets and he confirmed that he also felt they were squirrelly and hard to predict. I avoided flat Comets for a long time.
The flatter runs of Comets I have picked up recently are not particularly squirrelly and are a lot more useful than those old flat X Comets, so I've stopped totally avoiding them. I still prefer the domey ones.
I still am not really great at throwing the domey ones on a low line, though. I'm a pretend Comet guy. I like them and I throw them and I own a bunch, but there is a Roc patch on my bag. :|