Those were great episodes.
Regarding eating the Goa'uld, I recall talk of a paper on evolutionary biology that used computer runs to show that with relative immortals in the breeding population of a species, evolution slows way down, virtually halting. The long-lived members are obviously extremely fit, and their constant input of the same genes into the breeding population makes it much harder for any novel mutations to spread.
The Goa'uld provide an interesting example of this, where the dominant members have been dominating (if not virtually monopolizing) the gene pool for thousands of years, even though their rate of reproduction could be very high.
Getting away from direct biology, we've got the problem that their offspring will posses their knowledge and be every bit as smart and cunning as they are, such as Tannith, Klorrel (sp? Apophis' son) . The most dangerous adversary to any system lord would be his own offspring, who would already know his secrets and any weakness he'd been concealing from the rival system lords. Given how long the Goa'uld live, and that they're fully aware that they all seek power and dominance, there's almost no way that offspring wouldn't find the oppportunity to slay their parents, given a century or two focusing on Goa'uld who most directly blocks their rise to power.
Viewed in that light, by eating their own offspring the system lords are removing the most direct threat to their continued dominance. It has elements of Jerry Pounelle, Steven Barne's and Larry Niven's books "The Legacy of Heorot" and "Beowulf's Children", based on a species of African frog that survives by eating its tadpoles. The tadpoles don't reach maturity until the parent dies (and thus quits eating them).
So in closing a plot hole, they opened up a view into an interesting dynamic. The Goa'uld figured out how not to become King Lear.