I'm sure this was discussed on here about 9 months ago.
I don't think a cult hero has to be one that is not that good. To me they are ones who build up a special relationship with the fans. From the dictionary:
Alan Wright seems to have been mentioned because he produced average performances for a long time. Apart from the occassional Alan Wright - Wright - Wright chant i domn't remember there being a particular affection towards him.
As i only started going in the early 90's i can't comment on all of the players but the two that stand out for me are McGrath and Taylor. They are the ones where you could notice the buzz in the crowd, those players were special to villa fans.
Go outside Villa Park and Ian Taylor would hardly get a mention but he was special to us.
McGrath did win the player of the year but i even then i don't think other team's fans realised how special a player he was. He was our God, the player with something different, despite having messed up knees, a serious drink problem, not being able to train, having mental problems as a youngster, being hounded out of united. He was a true flawed genius.
To me, the way the fans revered McGrath makes him a true cult hero.
But thats only my opinion.