True, but that assumes a being capable of merging multiple strands of otherwise incompatible DNA. I'd need an extremely metamophic gene to use as a base in order to make that work, and even then it would be a heck of a process trying to get the desired traits to remain dominant. Much simpler to just enhance a single genome, rather than try to combine several.

EDIT: I really need to get in the habit of using the quote button... :P