One never knows when the following recent decisions of the High Court of Australia and of the Supreme Court of Canada may be useful:
Judges and witnesses
For some observations on how a prosecutor's decision not to call a witness may be dealt with by the judge at trial, see Diehm v Director of Public Prosecutions (Nauru)  HCA 42 (30 October 2013) at -, and on when a judge may call a witness, at .
These dicta may be useful in interpreting statutory powers that are not elaborated, for example s 113(3) of the Criminal Procedure Act 2011 [NZ].
And for discussion of the partial defence of provocation in Canada, see R v Cairney, 2013 SCC 55 (25 October 2013), on the requirement for there to be an air of reality to the defence before it has to be considered, and R v Pappas, 2013 SCC 56 (25 October 2013) where although there was an air of reality to the objective element of the defence (that the conduct was capable of being provocative), there was not in respect of the subjective element (that it deprived the defendant of self-control).
Repeal of provocation as a partial defence has resulted in cases on provocation being of limited interest in some jurisdictions. However, provocation remains a mitigating factor, and a relevant question may be whether it has the same elements in that role as it had as a partial defence.