I love the stack exchange engine and would definitely be interested in helping to create more open ended SE sites on Area 51 if SE would allow it, providing they maintain the Q&A style and do not degenerate into discussion forums.
SE is far better than other online Q&A sites I have found for a few reasons:
The best answers are always at the top (providing you're sorting by votes)
Answers are clearly marked, and you're not wading through a lot of comments or questions to find the answer
Anyone can edit posts, so the grammar and spelling is normally edited into something readable and easy on the eyes
The targeted communities ensure that everyone participating shares a common interest
The tag system makes it easy to find questions that interest you
The reputation/badge system encourages users to keep participating in the site, and is a decent way to tell how knowledgeable a user in in a particular tag or topic
Any community member can help maintain the site, not just moderators, which leads a lot more users helping with the janitorial work
I feel these things are what makes a high-quality Q&A site, and not specific rules about how a question should be asked.
Some of the best questions on this site are opened ended, and have many great answers that equally answer the question. Some might not have a single right answer to the question, while with others the determining factor in which answer you select is based on your specific situation. I find these questions a great resource for many users, and would not consider them "discussions"
But I'm not sure that SE will allow such a site.
Programmers.SE was originally meant to be a more open ended site where you could ask subjective questions, but at some point it was decided that the questions it attracted didn't meant the quality standards that SE wanted, so the site's direction got changed. I loved participating in the site back in its early days, and learned a lot from it, but have since quit participating because it is no longer the resource it once was for programmers.
You can learn so much through open ended questions that you cannot learn through targetted questions, because there is a lot that you don't know you don't know. So providing SE supports such a proposal, I would definitely be interested in helping to create and participating in a Q&A site that allows open-ended questions again.