I really need to relisten to it. I never hear good things about it elsewhere, which makes me disinterested in coming back to it, but sometimes the consensus is wrong. Although, the RYM average isn't bad at all, maybe it's just that people's expectations were sky-high and those are almost always impossible to meet.
It just wasn't what a lot of people wanted. An Opeth-meets-Porcupine Tree sounding album might have happened if they had made it around a decade earlier, but by 2012, there was no way that was going to happen. Porcupine Tree was on hiatus and Opeth had changed sounds completely. People should have expected something completely different, and that's what we got. But the identity of both musicians is still very clearly there - if anything this album is so great because both musicians are excellent at crafting very evocative atmospheres in their music, and that's what this album has as its main focus. Every single song is just so damn vivid in the mental imagery it creates, which is especially impressive because each song has a very different mood and atmosphere. Some darker stuff, some prettier stuff, all done amazingly.
If there's one other album it reminds me of, it's Comus's First Utterance (especially the song The Herald), which is a cult classic and also a very good album in my opinion. I would hope Storm Corrosion gets its rightful place as a cult classic eventually, but if the cult is just me and like, ten other people, so be it.