accident investigations and conflicts of interest
In theory there is always the possibility of a cover up or 'polished' report - there are too many parties involved (manufacturer, airline, insurances, politicians, victims' families etc.), many of which have clearly opposed interests and some of which would be ready to pay good money to have first look at the data and the possibility to 'edit' it.
Economists and anyone studying agency and game theory could write (and have written) theses on this.
I would personally argue for FDR/CVR data/readability to be independently verified by several parties and the data to be made public after incidents/accidents. This way everybody (including armchair theorists) can make their own interpretation and there can be a healthy discussion around the facts - potentially eliminating the possibility of cover ups or biased reports.
But then accidents are a sensitive issue - especially when people lost their lives - and of course CVR/FDR may only be a small part of the puzzle.
IMHO sunlight is the best disinfectant though. Transparency works wonders - in any latitude...