We are rebuilding a large web application from the ground up. We have several thousands of technical users currently managing digital products in a web portal with a complex account/user structure. It has security overhead and a legacy nature that complicates the process of installing third party analytics tools. The UI is a mess of bolted on, unscalable functionality, and so we're completely reconsidering almost every aspect of the platform.
I'm putting together a strategy for reaching out to existing users to validate our assumptions from the persona development process, and to attempt to work their actual goals into the process from even before the ideation phase. I need a communication process that provides optimal data capture, and that allows sufficient control of the conversation to keep it focused on their goals, outside the context of any UI.
The key points from a user interaction perspective are that I don't have anything visual to share about the new UI - this isn't user testing - and I need to ensure the conversation isn't hung on the hooks of the problems with the current system.
Does anyone have experience in managing this type of communication and implementing it in an agile development process? What type of communication tools did you use, and what are the lessons you've learned?