If you are writing Revit add-ins for more than a year, most likely you are already familiar with our annual API wishlist survey. I have been working with the Revit product manager to assemble this year's API wishlist survey. Here is it the link to the this year's survey:
Please take a moment to participate to this survey. It will take less than 5 minutes. The Revit product team will use the result of this survey to prioritize the areas to focus for API enhancement. We would also encourage you to give us a feedback you may have using a free form feedback section. If you provide the e-mail address when filling the survey, we will send you the result after the survey. (We will not sure your e-mail address with anybody else other than the purpose of this survey.)
The survey will be open for three weeks till June 20th, 2014. We look forward to hearing from you!