These guys at their prime i,e first two albums are the pinnacle of thrash. Nothing really comes close to their blend of technicality, savagery, and all out hellish speed. They make Razor look tame, they surpassed Slayer, and overall their discography is arguably better than Dark Angel's. Illusions may not be better than Darkness descends, but taking into account the fact Dark Angel tanked in quality afterward. I'm inclined to call Sadus superior
Maybe Cannibal Corpse guys were influenced by Dark Angel and Sadus - among other bands - (I wouldn't be surprised to learn they were), but no, I think you were tripping when you MISTAKENLY noticed that Cannibal Corpse came out of the mix between Sadus and Dark Angel.
You can't have Death Metal band from a Thrash band, after all, Death Metal just appeared, out of nowhere. It really didn't come from thrash metal, with a extra dose of aggression, no, no, it came by itself. :)