Hieronymus: The idea of a new variant has been proved with Assimilation (was called Ataxx when released). When the Ataxx rule of a knight move was introduced Fencer released a new version called Ataxx, and the old version of Ataxx was called Assimilation.

As i mentioned, most people prefer the Assimilation version, so even by introducing the proper rules to a game like Ataxx, does not mean people will prefer that version, even if it is the proper one.
The games of Dice Chess is still new, so its a good time to do it.

As for explaining the rule difference, good question, i would ask BBW to write it, he is good with words