The bug that I was talking about seems to be fixed. I am sure that was in fact a legitimate bug. I have been shadow speced since I started and played with that glich the whole time. Stopped playing for a couple of months though, must have been fixed during that time. What surprises me the most is that no one seemed to have noticed it. I mean the cooldown was actually starting from 30 secs, which is not the case anymore. Case closed
I wouldn't know anything about the spell being resisted to often. Never seemed like too much resists considering the number of undead players and lack of hit.