Thanks for bringing this back up Brian. I was just about to do the same :)
The only idea I'm personally opposed to is the "fork for every release" Though thinking of it as a live doc where we snapshot it for a release is not a bad idea. We could just have a WFLY project that we snapshot for every release. We just need to be careful about using versioning when writing the docs, unless it's a "Since WIldFly whatever" type of thing. We just want to avoid the "In WildFly x".
With regards to the linking problem, I'm not sure if we (myself included) are just linking incorrectly between documents or it's just a limitation of Confluence. It looks like most links are done like [WFLY8:Implicit module dependencies for deployments]. I noticed some don't have the "WFLY${version}" prefix so maybe that's the way to go. When you use the linking function in confluence it adds the doc reference to the link which could be part of the problem.
There are also docs that just point to old information. Like the main page references Java EE 6 getting started [1]. The Some pages are just dead too [2]. In some places, I tried to fix the ones I found in the WFLY10 docs, it just references the wrong version of WildFly. A lot of XML references too which likely point to older namespaces, maybe not a huge deal though.
Overall they're not bad. They just need a little TLC. I do think too there is probably some bigger chunks we can get rid of like a lot of the quickstart section since we have it all on GitHub. Also subsystem references could be replaced with WildScribe.
Anyway, I'm up for anything that allows the documentation to be consistent, easy to write and easy to use. The main attraction for me to asciidoc is being able to use git for versioning as well as being able to use variables. I don't however know how well asciidoc deals with multiple documents and combining them together.
Regardless of the direction I'm willing to put some time into fixing/updating it. I just think before we invest any time we make a firm decision on the direction we want to go.