Dreaming of a dead stranger means that you are worried about others outside of yourself. You are concerned about the welfare of others and this means that you have grown as a person. You are a stronger person and you will be successful because of it.
A dead stranger can also symbolize a ton of social growth though. This is because it means you have no need to be afraid of strangers anymore. This can be a fear in the most common sense of the word such as a paralyzing thought that they may hurt or kill you, or this fear could be rooted from the social fear of approaching someone new and attempting to make friends. In any case though, a dream like this suggests you may be past this stage of fear and you are ready to move on as a better adjusted adult. As silly as it is, this type of thing can be hard for others to overcome and should not be taken lightly.
If you have a dream about the death of a stranger, the meaning of it basically depends on how hospitable and charitable you are to strangers when it comes to you. If you are the type of person that usually keeps to themselves, then if you have a dream about the death of a stranger it basically means that you are becoming a little more aware of the world around you. You are realizing that bad things sometimes happen to people outside of yourself, but you have yet to form an emotional connection to them, If you have a dream in which you see the death of a stranger and you are the type of person that is supremely connected to the anonymous and to people that are not you then it means that you have just gone through something sad, through some sort of sadness that you need to help convey and sort through. Get help from everyone you can so that you feel more true to yourself.