TecP,
I think the only advantage of the smaller helos is that they can land in smaller sites than something like a Sea King. Other than that, if you can get a static line to a casualty then you can winch to a casualty and as you have already agreed, hoist ops are safer. The main reason I can see for using fixed line on a smaller helo instead of a winch on a bigger one is cost - not exactly putting the safety of the crew and casualty first is it?
If your man on the end of the wire is having trouble facing forward then he might need to look at a different harness - our winchmen wear a bosun's chair arrangement that allows them to kick freely and thus keep themselves facing forwards (most of the time).
I wouldn't do a fixed line rescue if I could possibly help it as it increases exposure to danger time for all on the wire as discussed on other posts.
A question - do you do fixed line ops at night? The best mirrors in the world won't replace a good winch ops hover patter, especially if your hover references are poor.
Winch out, rescue casualty, winch in then start treating the casualty on the way to hospital - I would not like to be recovered from an RTA just to freeze to death on the end of a 100' bit of rope!