In agile (from my perspective) you rely on constant feedback from the stakeholders (customers, Product Onwer, sponsors) and iterate on it - that's why it's crucial to have short sprints so you can contain the uncertainty and make sure you're heading in the right direction.

In the 'iterative waterfall' you usually split the work into several domains, with each iteration taking months up to a year. E.g. when implementing new core banking system, the first release could be 'move the customer masterhip into the new system'.

Sorry for misunderstanding, I meant that business processes are usually derived from the regulatory requirements, not IT processes. The following implementation is then affected by those regulations - again, in a way that limits potential differences between the desired outcome and implementation choices.