Can I submit an article just for the sake of useful feedback?
Submit your research to a workshop. Workshops are the kind of venue you are looking for: their purpose is to provide feedback on work-in-progress, with a fast review cycle and reviewers focused on a specific area of expertise. 

Submitting your research to a conference may lead to valuable feedback, too, but there's a risk that submitting work-in-progress research can leave behind a poor impression to some of the reviewers. In consequence, these reviewers may be inclined to give rather terse/useless feedback.