Gravity Forms is deliciously close to becoming a brilliant survey/quiz app for academics and researchers.
As an academic - I'd be happy to sponsor a premium version that offered enhanced survey/quiz options if you can find a friendly developer todo this...
Here, in order of importance is what would be required
1. Rating Scale Field - Users rate either a single (or list of) text items or thumbnails (option to link via lightbox to multimedia content) on a 3,5,7,10 or 11 point scale. Scale options of radio buttons, stars or smileys
2. Tag Cloud Field - Users select option from a displayed tag cloud (or if enabled in set up - optionally add their own tag) tag cloud can be pre-populated in set up. Expletive filter
3. Adaptive Multiple Choice/Check Box - Just Like Multiple Choice option, but if no option is appropriate - users can suggest (add) their own in text box at base of list. Next user sees list with added element (expletive filter - mark as inappropriate option).
4. Multimedia Vote Field - as standard multiple choice field but for multimedia content - users select preferred option from a gallery of thumbnails (linked by lightbox to video/images (uploaded or via embed code)
5. Twitter Field - As Standard Paragraph Text Field, but also optionally posts entry directly to a defined Twitter account, with custom hashtag and bit.ly link (defined in set up)
6. Upload Field+ As standard upload field - but users can submit document/image/media file - and it see previewed (or at least confirm upload is there - useful for uploading entries, essays etc)
Other than that nice to haves - but not necessary for V1.
I) "Quiz Mode" whereby form gives custom right or wrong response to entries and tallies up score (useful for term assessment)
II) Conditional Logic, if selection = A in Question 1, then display 2a underneath, if B then 2b (ideally with Ajax so no page refresh)
III) Basic Response Piping, takes user response from earlier question and inserts it subsequent question text (ajax)
If there is a WP developer out there - who you could commission to do this integration - I'd pay for them...