There's usually a couple of things to keep in mind when discussing sniper operations: historically the US military has taken a dim view of snipers in general; and the myths that the media has spun up by attaching the tag "sniper" to any whackjob who uses something larger than a Glock when committing crimes.

Looking back at Vietnam and the diversity of sniping operations there is an interesting exercise in this case (and I'm also going there to avoid drawing conclusions on recent events). In some regions they were used in a counter-sniper or precision shooting role; coming into play when fire was being received (a defensive role in many ways), while in others they were used to watch trails and engage insurgents (an offensive role). The roles themselves are generally neutral - it's command emphasis that has a major impact. Look at the 9th ID under Ewell to see some possibly major abuses of snipers, ROE, and metrics in general.

Another area that can come into question is selection and training, especially if there's a big push to increase sniper numbers. Most people really don't know or understand how much screening comes into play when selecting snipers...and I suspect some just don't want to know.

I'm sure folks like slapout might have some input as well, especially regarding LE snipers and considerations from their realm that might prove useful for COIN.