I don't really hate Opeth per se, but I think they have made 2 offensive albums: Watershed and Heritage. The latter is the more offensive of the two, just cause it's so bad written and reeks of wannabe vintage feel that I can't help but hate it.
The fact that I know many people who loves the band and gave it 10/10 BEFORE hearing any song doesn't help so much either.
The most weird aspect of the album is the 'out of place' feel that I've got from the vocals. I think Mike's cleans fit well some heavy parts and some semi folk oriented acoustic passages, but on Heritage, his voice sounds way too 'modern', the vocal patterns and melodies are mediocre.
If he released that shit under his own name, it would be more understandable, but equally mediocre.
In the other hand, the way Mendez is so audible and leading the way thru the whole album makes me think that he has a higher part on songwriting. I'm also impressed with Axenrot. It's not like his drumming is mindblowing or anything - still I think Lopez is way better - , but his work on Watershed was so mechanical and now it's very versatile.