the Workflow designer can not handle this dynamic assignment you wish. You could either put a text field in the decision where you type the name of the next step, then after the task, you have a lot of condition steps which evaluate if the value you typed into the text field matches a step - if yes, it goes to the step, if not, it evaluates the next step.
The other option would be to have one decision per each step which could be next, and you choose the next step this way.
However, I do not think that this approach is "best-practice" and currently, I fail to see any reason to do this.
The default "General Error"-Task already gives you the options to either repeat the task which failed, continue with the next step or just exit the workflow, usually this is enough for me. In rare cases when I need special error handling, I create such an "error"-Task assigned to the administrator.
Greetings from Germany,
Simon H. Hellmann
DocuWare System Consultant