I don't know if you are familiar with Scandinavia, but the "death rock" with Iron Maiden leads and screamed/shouted vocals was born in the latter half of the 90's mostly through Sentenced and Dark Tranquillity. In Flames was just the lesser known little brother of DT before they became a pop metal band. Old newsgroup postings from back then note that Children of Bodom sounds like Sentenced crossed with power metal.
Actually, “death rock” means something completely different and unrelated to what you’re implying it to be, as does death 'n roll, for that matter.
If I get your drift though, I agree with you: Sentenced were a good if not the best band in the early melodic death metal style - the kind also typified also by early At the Gates, early In Flames, early Dark Tranquillity, Eucharist, Ablaze My Sorrow, A Canorous Quintet, Decameron, Ceremonial Oath, Dark Tranquillity etc. The type of metal their "North From Here" album represents though is much more than just "Iron Maiden leads and screamed/shouted vocals", IE "pop metal". I dunno about Sentenced spawning millions of imitators though since many bands were doing the exact same thing at the same time, including At the Gates. Maybe you could elucidate me on this?
The “pop metal” you’re talking about is in my view something different from what I described, where Sentenced could be said to be an innovator. The major innovators in this Gothenburg style that took over I see as being Carcass (with Heartwork), At the Gates (SotS), Dissection, Hypocrisy (The 4th Dimension) and In Flames (first 4 records). I don’t see Sentenced being an innovator here. They (unnotably) changed sound on Crimson and so did Amorphis, to this new style (producing IMO their best album ever). As for Dark Tranquillity, I see them doing pretty much the same stuff Sentenced did on North From Here only two years later, whereas In Flames folky guitar stylings introduced something completely new.
The "Iron Maiden with a cold" schtick grates on my nerves since Iron Maiden neither invented melodic guitar lines in metal, nor are they the best example of it. If you're going to pigeonhole an entire style like that you might as well call Altars of Madness a more technical Possessed or Ildjarn a shittier Burzum.
The CoB newsgroup stuff you're talking about probably refers to Sentenced because they're both Finnish bands so it's an easy comparison to make.