Smich's lawyers introduced his criminal record IIRC. They must have thought that because his past convictions were for non-violent crimes, it may actually help his case. When MS decided to take the stand and testified to his GOOD character, he opened the door for character evidence to be admissible. DM didn't take the stand......
Even so, I don't see a huge discrepancy in what was allowed as character evidence for DM vs MS. DM did NOT come across as a choir boy. In fact, the character evidence against him that WAS allowed IMO was worse than MS. The thefts/missions.....multiple women....drug use/supplying friends with drugs/supplying MS with oxy....how MM felt about him....etc.
I understand why you see doubt, but IMO there was no miscarriage of justice as far as what was allowed into evidence. MS's violent and gory snuff film wasn't allowed (assuming bc it would have been too prejudicial). They were both bad apples.....the jury just wasn't privy to exactly how bad they were.
all MOO