Develop editable textile custom field
the feature to create custom fields made Redmine very powerful, much more than it already is. I usually use this feature to develop organizational processes, creating required custom fields where the user is obliged to enter some information before posting the issue.
However, when a new custom filed is created, you have the following options: text, long text, integer, float, list, date and boolean. There's not any option to create a field to type text using textile formatting, like on issues creation. The only option we have is the long text, where we can't even resize the text field.
As Redmine doesn't have this field today, I usually specify the deliverable of each task on the description of the tracker. Implementing this feature would allow us to have an specific and required custom field, thus obliging the issue author to define exactly what he wants before assings the issue to someone.