I am apparently one of the few that does not have a problem with the repeating riffs on the song "Deliverance". In fact, I don't want that end section to stop!!! But that's the way I am...sometimes, when I hear a riff or a section of a song that I like, I'll obsess over it, listen to it several times in a row to take in every nuance. Now, sometimes there are riffs I don't like as much--but when I hear a good one, I actually like the repetition of it.
2 of my pet peeves about Opeth's music are related to the first 2 albums (certainly understanding that there would be issues in the beginning, for any band), and I know the band has since dealt with them. The third I know was the result of some severe problems during the recording process, and I am understanding of that, even though it does mean I don't usually listen to that particular album by itself.
--The production on Orchid/Morningrise...Orchid definitely suffered, but Morningrise also had some issues...particularly that one guitar tone that for whatever reason, gets old after awhile (for me).
--The vocals on Orchid and Morningrise are kinda...high-pitched in the screaming sections, and I prefer what's done on the albums from MAYH forward. I should also note that Mikael has made great strides with his clean vocals over time, as well.
--The mixing on Deliverance...I wish it hadn't come out quite that way, but I give the band credit for doing the best they could under adverse circumstances.