With Blessed Are the Sick the band left behind a lot of the attitude, character and charm contained within their first album.
You think so? I personally think the only thing they left behind were the obvious Mike Browning bits (the cheesy King Diamondesque keys that just double the guitar lines at randomly selected intervals), and those added nothing and subtracted much anyway. Blessed are the Sick maximizes everything that is best about Morbid Angel (the instinct for weird, disconcerting, serpentine melody, a classically refined sense of pacing and construction and surgical rhythmic precision) while avoiding the weaknesses that crop up from time to time on their other albums (self-indulgence, a tendency to fall into formulaic ruts and songs that can become to bloated for full coherence).
Not to mention the production is a lot better on the debut. It sounds more organic and compliments the music nicely, the drums especially.
Honestly, the only thing I can say for the Altars... mix is that it is a little louder than Blessed are the Sick. The latter has a more robust bottom end and a crisper distortion texture that better highlights the heft and precision of the music. I couldn't care less about drum sound: drums are there to keep time and shade the edges of rhythm, there's absolutely no reason for them to be "interesting."