An interesting point and I'd have to say yes if you consider the punishment to be based upon potential damages.

Are you enhancing this visibility economics to other "ideas" as well? e.g. that the punishment for the killing some public figure should be higher than the one for some homeless guy?

It is, though. Killing the president would be reason for you to serve a longer term than killing someone else.

That probably has less to do with his importance in general than it has to do with him being a special government employee. For example killing a cop would also land you a longer term than killing someone else.

You probably wouldn't (or shouldn't) get a longer term for killing a homeless man vs killing Bill Gates for example.

Agreed. When he said "public figure", I figured he meant politicians, presidents, congressmen, judges, etc, not people who are just generally popular.

There's a difference between slander or property damage and murder.