This has been discussed extensively before (and I was among its supporters in the past). Some of the challenges with the idea you describe are that 1) the iNat community is so much larger than BugGuide that it could be difficult to determine what to include or not to include
2) different groups of organisms require different standards for identification, and a single template for ID guides might not work well for both fish, bees, and fungi, for example. 3) A wiki style format, like on BugGuide, works well for text but gets complicated if you want to make it look nice, and complex formatting or tables might not be possible. I’m not saying that a standardized solution couldn’t happen, but it won’t be perfect.
Instead, the ‘Journal’ tool has been used by the community for quite some time to develop ID materials, and enables a variety of formats. Some examples for flies include:
https://www.inaturalist.org/journal/upupa-epops/29497-identifying-allograpta-in-north-america
https://www.inaturalist.org/journal/edanko/27945-micropezidae-us-canada
https://www.inaturalist.org/journal/edanko/36353-guide-to-nematoceran-families
The challenge here is still that unless you hear about these journal posts in a comment on an observation or something, you won’t know they exist… maybe the solution is to make journal posts indexing other journal posts? :)