I am a member of tons of different Discourse forms. Most of which relate to programming and product design.
On every single forum I am on, I see the same thing as the last option for 90%+ of polls:
Whether the poll itself is the main part of the topic, or just a “what’s your opinion”, having an “Other (Please Explain)” option lets user’s voice their opinion with details, not just a vote.
Having people explain can be extremely helpful to the OP, compared to just a vote will tell them X or Y, without any reasoning.
The main issue with having an “Other (Please Explain)” poll option is that not many users will sift through the various replies to see what contain the ‘(Please Explain)’ part of the poll.
The simple solution to this is having a poll option that lets user’s add input. This could look something like:
For viewing answers, the poll can show the normal chart/graph (depending on what type of poll it is) as well as a drop down (summary) of the explanations. These could either almost look like a reply (with the user’s account linked to them) or anonymous depending on the poll itself.
Adding this feature would allow people to incorporate other answers to polls that may not be long enough to make a reply, or just add more detail.