I think one immediate and reasonable change would be to have HIA’s conducted by an independent body. At the minute, club doctors conduct pre-season baseline assessments and the in-match assessments. While I’m not questioning their integrity, they are on the payroll of the organisation who need their “assets” on the pitch.
If the RFL conducted/appointed independent specialist doctors to conduct ALL of the HIA assessments, both pre-season, sporadic review in season and for in game knocks, they could ensure true independence to the tests. Which, if nothing else, would be a mitigation further down the line for future cases.