heedm,
The idea in deciding to land is that the pilot has decided that the aircraft is in a safe position to land, and that the landing environment is clearly in sight. Letting down below minimums is one of those acts, like pulling triggers and ringing bells, that don't allow any "oh, I changed my mind!" second thoughts.
Yes, you should go back up if you find you really can't land (although in my entire helo career I have flown exactly ONE missed approach for real!), but there is no rock solid procedure that assures that the below-DH-missed-approach will work.
The concept I was shooting for is that the helo approach ends when you touch down, and that for most helos a sizable slow-down is needed from the DH/MAP to the touchdown. This slow down will keep minimums pretty high until we slow the machine down while still IMC. The next boundary we will cross with helos is to become truly VTOL aircraft, and abandon all those airplane procedures and perform a truly helicopter IMC landing.