Yeah, I know about the 45RPM version, but I only found out after I bought the 33RPM (!). I agree, there is a lot of complexity happening, but there's a lot of complexity in a Mahler symphony and I have a few of those that sound stunning.
Decent sounding metal (and I use the term broadly) albums:
Faith No More - 'King For a Day, Fool for a Lifetime'
Soundgarden - 'Badmotorfinger' and 'Down on the Upside'
The Melvins - 'Stoner Witch'
Prong - 'Cleansing'
Leeway - Open Mouth Kiss
Nearly the entire Rage Against the Machine catalog, and most of Clutch's albums (especially Elephant Riders, recorded/mastered on a Tim de Paravicini modded Studer, which shamefully has never been on vinyl). There are more which I can't remember off the top of my head.
And, of course, there's the past - lots of good sounding Zeppelin, Deep Purple, Sabbath, Rainbow, etc.
What's your list of recommended metal LPs?