Please be very careful with #5
Maybe there could be system, similar to the metabolic re-sequencer, that can change a characters personality completely ingame. Like some Psychologic-meditation inner-change crystal-ball ;)
Personally i like that charaters differ a lot from each other and think it should absolutely stay that way!
As said above: Evening personalities out makes them less unique and thus less interesting imho & Some personalities are already beautifully multi-faced and change their mind about their lifestyle and body perception in different situations!