I think if a person made a complaint to law enforcement, they could get a waiver - or maybe even a court order - to record a specific person for a specific time for a specific reason. Maybe that should be easier, but I don't think the process should be any less regulated.
The whole point is that you should be able to record now, and handle any permission/admissability later; and you shouldn't require cooperation of government beforehand - it's likely for police or court to say that your case is not important enough for them; but it's not a valid reason to restrict your ability to protect yourself.
What you intentionally say to me isn't your private secret anymore - if I had the right to hear it, then I have the right to remember it and to repeat that to any court; and I should have the right to remember it perfectly&permanently on a durable medium, and hand at to any court as valid evidence. In short, it makes sense to require permission of a participant in recorded conversation, but not all participants.