Well I decided to check out the rest of Heritage on youtube and fuck do I have some mixed thoughts on it. I don't have any descriptive thoughts yet but after a full listen I just don't feel like it fits. The music isn't bad, I like quite a few songs but there are several times where it sounds like Opeth trying to mimic other music rather than an original band. That may be due to the fact that Mikael wrote most of the material (as usual) and that's why it sounds like a copycat of a style. It's a guy that writes most of Opeth's music trying to step beyond his natural writing style, maybe he should have started a seperate project where everyone contributes to the music.
To summarize my overall impressions, I liked the music but I don't see myself listening to it for long. I think it sounds like an ego-project that Mikael pushed for and I don't think he alone had the chops to make it convincing. Should have been a solo album or a seperate project he doesn't govern.