There's no question that it would require resources, so that's just a decision: does the government want to commit those resources to improving the experience that complainants have in the criminal trial process?
Also, it has to be just as a matter of common sense. True, oral decisions and written decisions are different. For any of us, if we're drafting something that we know is quite likely to end up on a database for the world to scrutinize, it's going to look different from something that's recorded in court but is, in many cases, likely to be heard only by the individuals who were present in court that day.
Again I'll go back to the example that the CBA used, which is the Al-Rawi case from Halifax. He issued that oral decision without making reference to a single legal precedent in a very difficult area of sexual assault law, assessing consent in the context of a very intoxicated complainant. It strongly contrasted with a similar decision out of Ontario, also involving a severely intoxicated complainant, but a written decision, where the judge surveyed the case law extensively and wrote a considered and thorough analysis.