For the improvement adverse: Minimal change.
HFS-23-m-oldstyle.zip is available at
http://software.run.placeBuilt fresh from HFS2.3M original source, adding Leo's macro security patch, and the exec macro is disabled. Featuring the original defaults, the original default template, etc.... Not recommended for those new to HFS. But, HFS2.3m-oldstyle can help the "Don't Change" crowd to experience that in a real way.
For somewhat more comfort (optional) there is 'HFS 23 style template V2' included in the zip file.