The 78 feet deviation by the Mil Heli is not the cause of this accident . I hope the lawyers during the trial do not focus on that and minimize the rest .
Bit of historical background : when designing this route decades ago they must have followed basic ICAO/ FAA principles . separation IFR-VFR is 500 feet . allowed deviation then was 100 ft either way , so even if one a/c is 100ft above and the other 100ft too low , there would still be 300 ft separation preventing a collision ,
When that was introduced decades ago I bet you a bottle of (real) Champagne that the procedure was use of that route 4 was restricted during RWY 33 arrivals and RWY 15 departures. It was one or the other but not both simultaneously .
How , when and why , over time , did it degraded to the point that this restriction could be disregarded would be interested to investigate and unveil . The why I think we know, i.e. enabling to move more and more traffic, but when and by who we don't. How and on who's pressure did the numerous previous incidents got disregarded is another question worth asking . Not why the Heli pilot was flying 78 ft too high .
Throwing the Heli pilot (and perhaps also the controller on duty) "under the bus" as you say in your country, would be so wrong as it would prevent getting to the truth and learn the real lessons of this accident .