Ten animals would be absolutely fantastic, if they just adapted some of the existing rigs, I think that is definitely possibly. I think the real issue is the cost of that dlc, because for many of us, we would gladly hand our money to Frontier, but would the majority of the players feel the same? That is a tough question, you are probably in a better position than me to make a prediction.
I was under the impression for quite some time that no player would refuse a beefed up DLC with a substantial line up of animals and scenery but some of the opinions around here often do not show that, so who knows.
10 animals 500 + scenery items = 20 euros? could it work? I think that is the deal of the century, but my opinion would probably not be a popular one. I would not expect them to include different rigs, as many pointed out, an Asian Small Clawed-Otter is basically a modified version of the offspring of the Giant Otter, a Babirusa is just a warthog, a Gaur is an African Buffalo, a Binturong is a Red Panda, and the list goes on.
There animals that of course would take additional resources as their animations would be very different than anything else we have in game, Gibbons would definitely fit this criteria, as not only they behave quite different than any other primates found in the game, but brachiation is as important in the game as diving and flying in my opinion.
Clouded Leopards and Sun bears at first might seem like an easy task, but their animations would also be very distinct from other cats and bears in the game. As both species have pretty unique set of behaviors and like to climb. Climbing would ideally be more polished and include different variation of new animations. This can easily be accomplish with enrichment items, simplifying the process.
It would definitely take more resources from Frontier, but it has the potential of paying off, if the players get behind it.
I agree ten animals would be fantastic, but asking them to double animal production, include game changing features, include more scenery, and have scenario parks is a bit unreasonable given the time frames, especially some would not be willing to spend $20-30 on a DLC.
I have never been convinced by the this animal is close enough to the other one to use the rig with such ease(outside of wolves, bears, some deer), and I struggle to find how these rigs would be as simple as claimed.
I know you are well versed in Zoology, moreso than I certainly, still...
Red Panda's typically weigh 7-14 lbs and top out around 2 feet. Binturong's can weigh up to 70 lbs and hit 3 feet in length.
Binturong's have a significantly different coat and facial features. At first glance, they do not look much alike, even if they share some behavioral characteristics. I would be quite dissatisfied if we got a Binturong that looked a foot and 50 lbs light and had the same fur structure of the red panda just to add a mediocre rig to the lineup. They may share some behaviors, but both have unique behaviors that would be expected/ a let down if the Binturong only behaved like the Red Panda rig acts. Walking, climbing, and more would need to be reworked as they move differently.
The Gaur can be over 3 feet larger in length than the African Buffalo and has a much longer, narrower neck. The Gaur's legs are different(therefore their gait animations would need to be modified) and the neck is closer to the ground. The horn sizes and structure are quite different. The back of the Gaur is much different in build than that of the Cape Buffalo.
It was a while back, but I believe that they posted a statement/video (Though I would be hard pressed to find it and it may have been a message board) saying that sometimes reworking a rig is more difficult than starting over in trying to get the animal to somewhat match its real life counterpart. A gaur with the same back, neck, legs, and size of the Cape Buffalo would cease to be a Gaur. A binturong with the same fur texture, weight, and facial features of the Red Panda would cease to be a Binturong. Some species work for reskins easily; though, those are the ones that are complained about the most (bear, wolf, etc).
I feel a lot of the just make this animal with this rig are not quite as easy as many are thinking. Not to mention they would still have to include that animals natural behaviors, zoopedia information, coat variation, sounds, and more.