I was wondering if it would be possible for someone to make a sticky topic in the DOSBox forum, explaining that DOSBox 0.74 is the last official buld
That is the latest official build, not the last.
and listing what unofficial later builds there are their enhancements and (if any) regressions their enhancements and (if any) regressions, and what build is recommended for any specific game or whatever.
Why should the dosbox devs bother with unofficial builds when they are busy working on DOSBox.? That is a job for the community.
As it is, fairly often someone posts asking about v0.75, and they are told to use an unofficial build, and pointed towards the builds (as in Next Dosbox update?), but I think that newcomers (and even oldies like me, who don't use DOSBox too often) would often be confused by the different unofficial builds.
As with any project you should always use the builds provided by the project itself and not unofficial builds. DOSBox is not that hard to compile, if you can't compile then pester the DOSBox team to provide an accessible SVN build. IIRC, Qbix has one already but it's not promoted heavily. Prepare to be disappointed if you want whatever is fashionable, it will be pretty much the same as DOSBox 0.74 but with all the fixes since then.
A sticky that listed the stable versions of the unofficial builds, along with a quick guide to how each build compares to the others (i.e. someone might want to have a snapshot function, but doesn't care about long file name support), would help us less DOSBox-savvy people to decide what version(s) to use, and the sticky could be updated every few months or so, or after important releases, to reflect the new builds.
Use the official build, use a clean SVN ver. That's the official stance. Unofficial builds are not stable as far as we are concerned.
If tracking patches applied to unofficial builds is something you care deeply about then requesting access to the DOSBox wiki and posting the information yourself would be a good plan.
It may be worthwhile to gather all the patches out there and list a justification for why each patch should be included in DOSBox as well as how difficult it is to maintain the patch, what OS it's compatible with, if it is for non game purposes, what license it's under, etc etc.