This is a terrible idea.
Maybe it would work if questioners on the whole could write clear and focused questions: As it stands, the majority of fatwa questions simply ask what "Islam" says about something as if there's any single unambiguous answer, ignoring the fact that there's over fourteen centuries of differing opinions and schools of thought on pretty much every topic imaginable.
Maybe it would work if answerers on the whole had the basic critical skills and training to actually formulate a fatwa and the recognized authority to do so: As it stands, the majority of fatwa answers simply copy and paste already written fatawa from other sites as if they were universally applicable to all situations and all madhahib, or even posting segments of mutually exclusive fatawa in the same answer and formulating a new ruling that nobody actually follows.
Maybe it would work if the community on the whole had healthy voting practices that ensured that correct and useful answers rise to the top and incorrect and useless answers sink to the bottom: As it stands, proper voting — up and down — is very limited on this site and often overwhelmed by users simply voting based on opinions they agree with regardless of how well-written or useful it is to the question.
But that's three very big maybes. Even if all these conditions were met, it would still require the community to ensure that these questions and answers stay constructive, which would be a significant effort given the sheer quantity of non-constructive posts that such questions would attract; quite frankly, given how often this topic was brought up in the past to little to no enthusiasm, that's just not something the community is willing to do.
Without those three factors and a community willing to enforce them, all you'll be getting is a bunch of people who don't know what they're asking for getting a bunch of opinions from people who don't know what they're talking about with no way to determine which one is better than any other.
If that's what you want, there's already plenty of Islamic forums out there which do that. We want this site to be not that because — given how often those same questions are getting asked with nobody agreeing on an answer — that was obviously not working.