Cougar, out of Halifax and St. John's (Canada), have been operating to lower minimums for years now.
Really though, to effectively market IFR helicopters we DON'T need lower minimums. The few extra days of flying each year would only marginally improve performance.
We need IFR approaches to helipads, not runways, more heliport access to population centers, not airports, and effective icing protection/prevention.
With those improvements to the system, we'd be in business.