DAMN YOU MEATBALLS!!!!!
I agree stealth is an important part of every mission,and be a chameleon in every situation makes the gameplay more interesting and realistic, but i'm looking forwards for something more than simple stealth; a system that would allow us to resolve a mission in total different ways using our personal skills.
For example instead of just sneak in sneak out, i could call off my fixer for get a copy of the passepartour of the office ,contact a friend of a cousin for get a turn in the garbage man truck and get in unseen. Than finally i want to be able to blast everyfuckingarasaka i see, but that,is another story.
Actually you can go brutal even while sneaking but that's up taste. I'm not into complete non lethal plays either as ghosting turns soon into a quick loading and saving geocaching.