NVG's are still a BIG issue. As far as I am aware the civvy NVG rules state that they are a back-up to standard night techniques. I also believe that they cannot be used at low-level (below 500' from what people tell me). That is of very little use for SAR and if the civvy route is chosen then these rules will have to be looked at again. I may be wrong is I haven't read the rules myself.
I agree that MCA's roots are in overwater rescue. However, if the whole UK were to go civvy then who would do the overland night SAR (granted that not all overland night SAR needs NVG's but a lot does)? If I were to choose between FLIR or NVG I don't think it would take me too long to decide.