I believe it would be beneficial if we consider having the improvements fall under categories/components. To this end, I am proposing a few:
1. Having different classes of chess variants, as is seen in IAGO Chess System, with one of its purposes being to help provide a structured guiding of the evolution of the game:
http://www.chessvariants.org/index/msdisplay.php?itemid=MSiagochesssyste
2. Having different formations, that meet guidelines, as is seen here:
http://www.chessvariants.org/index/msdisplay.php?itemid=MSmultipleformat
3. Categorizing a standard set of rules variations, in the form of mutators. JP Neto explores this here:
http://homepages.di.fc.ul.pt/~jpn/cv/mutators.htm
4. Standardize a list of the names of pieces that fit certain move types.
These are just a few. I am fairly certain some others have slipped my mind.