In case anyone was interested in what I eventually did, here are the details.
PHASE 1 - Looking for large list of tasks
I decided that the most efficient way will be conducting a simple survey among my colleagues. It was impossible to schedule a meeting with a huge number of participants, and it would be extremely difficult to facilitate such workshop.
Also, in first iteration I did a simple brainstorming with a smaller team of participants, but it proved to be futile. The way I communicated what I wanted to achieve was wrong, so obviously I had to correct this. But also, people were influenced by each other, which in this case, was mind-closing. Participants oscillated around one narrow area of the system instead of think outside the box.
But enough about what didn’t work.
I created a form in Google Docs with few questions.
- I asked them to describe the biggest value that according to them our system gives to its users.
- As a second task, I asked them to enumerate the most important tasks to the users, described what characteristics a task must posses, and gave them examples of personas they had to have in mind when enumerating the tasks.
These two questions gave me a lot of insight into how particular departments are thinking about the product. The reason I asked those two questions is that I wanted to make them think top-down, I asked them to think on a very high level (about abstract thing such as a value) and then I asked them to go lower, into more details. I thought ot would direct them to think about the most important tasks. What suprised me, though, is that sometimes people were able to talk about the values but not detailed tasks and the other way round.
Anyhow, I ended up with a nice list of more than 100 tasks, which I then shortened by looking for duplicates and eliminating actions which in effect users were able to accomplish, but the system did not have such a function (e.g. checking profitability).
Now I’m working on creating an actual survey to be sent to our Clients and might update this thread later. Anyway, I will be more than grateful for all your thought on the process, feedback, critique, hints, etc.