Right, they are 6. The thief is also present in Oblivion, but what would be his characteristics? Increase the chance to stole?

The sex is only a choice. In MM6 the sorcerer, archer and druid can be male, depends of the portrait the player choose.

About changing how luck works and adding the concept of dexterity, this is a work for WoG team, I am far from being able to script that. One has always the ideas that he can complete.