I'd like to see a way of tracking a few things about "egg".
First, I'd like to be able to see exactly how much it's adding to my CpS, not just being given the +9 statement with no modification for my multiplier.
Second, I'd like to see how many cookies I've generated from "egg" over the course of my run. Perhaps it could be added to the building list once purchased?
The second suggestion could also open a few new achievements: generating some number of cookies from "egg" just as there are achievements for generating cookies exclusively from the various building types. Of course, since you can only have one "egg" and it doesn't generate very much, the thresholds would have to be low, but I think it would be an interesting addition.