Katatonia are one of those death-doom bands who, like Anathema and Paradise Lost, more or less walked away from the death-doom subgenre after the early phases of their career. (In particular, in playing an alternative-progressive metal style influenced by Pink Floyd, they seem to have been riding the Anathema bandwagon just a wee bit.)
Listening to Dance of December Souls, I find this a crying shame, because back in the day Katatonia seem to have really nailed the death-doom style and given their own spin to it, especially when it comes to the inclusion of light progressive elements here and there.
In particular, there's some delicate keyboard work from special guest Dan Swanö that on the one hand plays a similar role to the violin in early My Dying Bride in terms of providing a beautiful, haunting counterpoint to the more gruesome and abrasive aspects of their sound, but which inevitably gives the album its own particular texture. On top of that and some of the gothic influences that more or less all death-doom bands seem to slip in sooner or later, there's also some influence that seeps in here and there from early black metal, creating perhaps the richest bouquet of carefully chosen and arranged styles offered in death-doom at the time.
As a result, whilst latter-day Katatonia is certainly not my cup of tea, I'm going to have to make a point of exploring their early discography, because clearly there's some gems here that I've been overlooking.