I'm not going to tell you all about their roles,since you have many lessons on it. Seeing the modern complicated nature of warfare,strategy etc,I often think that once it could be one man army within a five/six men army,ie. there will be no separate designated men in the team of Sniper,the Spotter will be Shooter or vice versa. Do you think any possibility of it in future combat,or you just call it as against doctrine.
Maybe not against doctrine, but certainly against military finance. Why pay two guys when you can pay one? Also, one man with all the technology available today is probably just as capable of fulfilling the role of a scout/sniper.