Indeed it is a trade-off. And leaks revealing the dirty tricks of the rich and powerful make me wonder how effective KYC and similar controls are in practice. Yet it's that very visibility that motives people to act.

So perhaps the ideal is a sliding scale. The more powerful you are then the less anonymity/privacy you should be allowed, at least in financial or political matters.

Careful what you wish for, it's a double-edged sword: do you really want anti-abortion activists abusing funders of Planned Parenthood...? Or anti-immigration extremists harassing funders of NGOs who help Afghan refugees...?