I think the option descriptions should stay. And I think they should double as summaries.
Intros are important. There's a reason they're ubiquitous. News stories, Wikipedia articles, good presentations, etc all have them. They tell you what to expect and if spending time on reading further is worth it.
And it should make the site more valuable to those that don't wish to even skim the pros and cons.
I don't think the option descriptions should be removed because the quality of them is poor currently (repetitiveness among options, marketing copies). If we agree that, if done right, they add value, we should focus on setting a good example, educating contributors, and making the purpose clear in any other way possible.
IMO, option descriptions, if done right, make reading the content more comfortable.
As for question level descriptions. Don't really see a need for them.
There are rare cases that a question needs further explaining. Like the linux wm/env thing. But I think it should be a notification set by a mod not a description set by a user. The same notification system could be used for deprecated topics, astroturfing warnings, etc.