Speaking as someone who has been flying heavy metal into and out of the states for years, I find this accident obviously tragic but entirely unsurprising. I have had multiple instances of close calls with helicopters at various US airfields over the years down to completely inappropriate visual clearances being issued to the helicopter traffic - including clearances to fly under the active approach. On occasion helicopters appear to have taken it as almost a challenge to get as close as possible.. almost waving distance on one occasion at SJC. Apart from the risk of collision this is incredibly distracting for the crew of the other aircraft whose primary job at that point should be the monitoring of the flight path. Couple this with the practice of operating TCAS in TA only (as appears to be permissible in some instances for local US carriers) or indeed RAs being inhibited due to the low altitudes involved, and you have a recipe for disaster. Especially at night. And that is before we get on to the, all too often, casual level of R/T employed in the US.
Hopefully this event will spur a wider review of such practices rather than narrowly focusing on heli-lanes in the vicinity of Reagan.