While I still need to read this paper in detail, I'm not sure their only change is to this scaling of the update.

The `koan` CBOW change has mixed effects on benchmarks, and makes their implementation no longer match the choices of the original, canonical `word2vec.c` release from the original Google authors of the word2vec paper. (Or, by my understanding, the CBOW mode of the FastText code.)

So all the reasoning in that issue for why Gensim didn't want to make any change stands. Of course, if there's an alternate mode that offers proven benefits, it'd be a welcome suggestion/addition. (At this point, it's possible that simply using the `cbow_mean=0` sum-rather-than-average mode, or a different starting `alpha`, matches any claimed benefits of koan_CBOW.)