Thinking about it again, I quite like the current implementation. It forces you to plan ahead to max your wildlife. Cut down/improve single forest tiles and leave larger forests untouched. It feels like being a curator of the land.The initial idea was to just give only one wildlife and that's it, then I thought about adding a chance of spreading to adjacent unimproved forest/jungle tiles (and adjacent only) as a sort of reward for not improving tiles with a lumbermill and choose to preserve nature instead.
I didn't have maximization strategies in mind when I devised it, in the sense of choosing as first plot the one with the most forest/jungle tiles around so to maximize spreading possibilities; it was not the point and it isn't worth the effort of coding it imo.
From an economic point of view lumbermill should be still the more convenient improvement because its construction hence its yields are a certain outcome depending on the player's decision making (you send a worker there to build it) while wildlife diffusion is as exogenous as it should be (depending on a random draw). So strategically speaking you can choose to maximize wildlife resource diffusion but still it would be a less optimal choice than having carpets of lumbermills as it is in reality (destruction of Amazon rainforest enters the chat).
However one can technically exploit the reforestation mod to put forests/jungles next to a wildlife and affect the resource spread more directly.
I played a bit and like the civ. A lot of bonuses from diverse resources/terrain. This allows you to work with any land except too much water. It also does not force you into a specific pantheon or tech path, save for revealing most resources early. This can delay your science since you would not beeline for science buildings. The zimbabwe castle seens very strong for science.
Overall, I favor authority into fealty. Authority for the border pop yields and fealty to boost your defense and get more science from UB1. Also, you want to fight a lot to train up your UU1. Later, imperialism can be a thing as you want garrisons everywhere and you have the wildlife monopoly to boost.
Overall, this policy setup guides Zimbabwe towards domination. This is interesting since they have no significant combat bonus or direct yields from fighting. On the other hand, most of their bonuses scale well in a wide empire.
In the other hand, science can be a thing if the UB1 scinece from city CS is enough to make a difference.
Pretty unique feel to play.