I read the text of the Citi DG - the analyst's take. I was unimpressed. The downgrade text continued the analyst tradition of taking old news and making it seem like it is next quarter's news. I already know that Western Union has moved past the issues itemized in the DG.
Why would revenue risks to compliance be unique to Western Union? In which money transfer space does regulatory compliance not operate? If the sender switches to a competitor, he will find the same compliance requirements.
IMHO the CFO was canned because of the unexpected size and poor communication around compliance cost increases. The CEO probably thought he had been made to look bad for investors. I don't think there is anything else happening.