The damage is done. Coastal development only goes one way... natural ecosystems like our dynamic shoreline are developed, and once developed, they're gone for ever. It never goes the other way... tearing up developments and re-establishing natural ecosystems. Due to dramatic and permanent development along the coastline, we have limited our options, and at this point we need to cut our losses. The best options, including reefs, are expensive and unpopular. The investments required would be huge, and there's no way we can be sure they will be effective until we make the leap and do it full on. Mini reefs do not serve as models for large scale reef systems, because when you scale the whole project up, different forces and dynamics begin to come into play.
Read Orrin Pilkey's work... his first research was a real eye-opener, and he was totally blasted by other, more short-sighted scientists and politicians with their own agendas. We're learning now that he was right.