AniJen: Exactly what I was thinking. With such a large empire there would definitely be internal conflict possibly revolution with a) morphing capability presuming the blue box is found after taking over Earth b) the massive massive sheer number of potential human hosts which are far better than Taxxons and Gedds.
When someone takes over a country they also absorb into their culture all the things about the culture they enslaved whether they intend to or not. Considering that Yeerks inherently do this anyway it will DEFINITELY bring about great change. Remember the Visser One chronicle? (If anyone read it) she almost had a complete turn around based on her singular experience on Earth.
In terms of intelligence Gedds, Hork Bajirs, Taxxons. They're not particularly smart/advanced enough to give the variety and potential that humans have come up with. I mean even the Andalite(s) couldn't come up with the things us "backward humans" have done. The best the Hork Bajir came up with was knowing which type of wood to eat. Humans have created the ultimate "cinnamun bunzah"!
Okay back on topic to would the Yeerks have stopped invading Earth. It's quite hard to say but based on the assumption that the enslavement of Earth does not bring about an epic proportional revolution we can say that based on the propaganda control of their government Earth would not be enough. Sure a lot of Yeerks will be assigned to babysitting our planet but from past experience they usually end up stripping a planet of all resources for furthering their empire.
Actually in fact there were at least two instances where Earth was taken over so we do know what KA thought would happen. So yes on the list of the Yeerk agenda given that no revolution occurs:
- Molding Earth for Yeerk purposes
- Making Visser 3 member of council
- Wiping out or enslaving Andalites
- Wiping out or enslaving any other similar level of threat
eg. Kelbrid from the last book ever of Animorphs for those who didn't remember/know (SPOILER) the Andalite space neighbours who don't want trespassers - Exploration
- Meeting new-Howlers replacements and enslaving them if possible
- Meeting Iskoort in the far flung future and mocking them and then
- Getting beaten by superior (tech/numbers/combo) of aliens or internal conflict
Let's face it with possible Andalite technology, human numbers, human ingenuity and possibly several dozen other species and/or planets at their disposal the Yeerks aren't exactly going to just sit and play nice with their brand spanking shiny new hosts. They would have to have a massive change in government after conquering Earth to change their minds and even then they wouldn't just give up all their hosts and revert back to Kandrona lit swamps.