Consider the control objectively. Ask yourself how the user normally interacts with the type of accordion you envision and then see if that interaction fits the scenario.
These are the characteristics of an accordion:
- few panels
- first one is optionally open on start
- click header to open an accordion panel (optionally close all others)
- click any header in any order, no dependency
- information in panels not dependent (i.e. no restriction on which panel you can view in what order)
If this is not what you want, either don't use an accordion or don't make it look like an accordion (i.e. headers might not look like something I'd want to click).
Here's an idea:
I just used a good form to register for a course. It had an accordion-looking left panel with green checkmarks for ones I've done. They were not labeled as steps. The middle panel showed form for each panel.
I started in a workflow with the first. At each "step" I could "Save and continue". If I left and returned to the site, home page said "Resume registration where you left off...". However, at any time I could click any of the panels in any order to fill in any of the information. The checkmarks on the left made it clear which steps I completed and what is left. When I completed all of them, it wasn't really clear what to do (I think this could've been done better). So I either clicked the home page or a new step appeared... I can't recall. In any case, I was now at a page showing a submit/confirmation/you're done content and button.
I think something like this is a good way to create workflow that is clear but also flexible. There was no confusion because it didn't really look like an accordion, but I liked the ability to fill in info in any order and go back directly without traditional Next/Prev pagination.