Not really. In fact, I was thinking lately of trying that as I figured it would be nice for my gnolls to have a constant flux of things to hunt in their borders. But I also thought that it may be a real pain to have Spiders and Griffins roaming inside... Maybe you should tweak their power a bit?
I decided to remove animals from borders. They should move fine if caugth inside, but should no longer enter on their own.
Also, I tied some animal spawning to Techs. Animal civ will now get techs at the same rate as barbarians (orcs) and griffons, spiders, sea serpents and krakens I tied to a tech. Actually, I rarely see any griffons/spiders at all now, probably will have to work on it some more (or do AI autoplay beyond turn 120). Seen some gorillas, too
Speaking of animals attacking cities, I once had a city captured by a Hawk.
I can see arguments either way for animals inside borders but, in general, I think there are still too many animals. They spread like locusts in areas that aren't settled quickly. Like every tile ends up with an animal on it: Last night was the most I'd seen: I stepped on a hill and there was a square of about 25 tiles (5x5) with 19 lions on it!
That happens if there is a lair and neighbouringh civs are either animal friends or not active in exploration. Normally, ther are not so many animals.
Ahwaric: One thing you might not have imported in CvUnitAI was a tweak which should lead to the AI sending more defenders with their settlers, and sending a defender with their workers. Doesn't work very well unless you have also increased the default number of defenders they try to keep in each city so they have spare units to toss around without risking city loss, but works fairly well if you did.
Thanks for the tip, I have added it. It does work even without forlife tweak, and I think forlife is too strong. Civs hardly expand because of so many warriors.
While autoplaying, I've seen the AI escorting its workers and its settlers. However, I added a tweak in python that forces the AI to build at least 3 warriors in a city before building anything else (or maybe this is 3 warriors in all the empire...). But what can a warrior do against a giant spider?
I do not like python AI setting as it seems to limit it too much. I think the survival rate is ok now, and I did some extra tweaks, so most civs started to research agriculture. I also have increased the preference to build cities near rivers.
My main problem now is to remove lairs that pop next to capitals as they cause some serious problems for the AI. I will try to secure a zone free of any lair.
The ability the Ljosalfar (and Svart I would guess but haven't confirmed) get with the Subdue Beast promotion doesn't work; the one whose button looks like a dragon or a wyvern. I assume it is supposed to be either "Challenge Beast" or "Mesmerize Beast" but it doesn't actually do anything at all and is called "Mesmerize Animal" just like the one you get with Subdue Animal but with a different button.
Thanks for the info on challenge beast, had some bugs.
But why do you have to get rid of animals? Just let them be, they will protect your land and only provoke the ones you need to settle in cities or use as totems.
The game seems very stable now. I had a few CTD's, having to do, IMO, with a vine stack popping up after searching an animal lair. Something happened then when I tried to attack the square that caused a CTD each time. Unfortunatelly I don't have a save, but I'll try to get one if it happens again.
A little off-topic from things I wondered while playing: Is there a way to remove haunted lands ?
Thanks for the info on stability, at last some good news

If anyone gets a repeteable CtD, plase save me a save to work on.
For haunted lands, try one of the following:
sanctify (remove)
vitalize (forest)
burn (burned forest->forest)
The AI seriously can't seem to handle the animals: I haven't lost a game since 0.23a on Immortal+ and I am not the greatest player ever.
As I have mentioned above, that should not be a problem any more. Also, AI got some extra bonuses and should be more competetive now (hope so).