I'm sorry about taking so long to answer. I've had some wild days.
Great cobra's reward is somewhat better than the wolf pen's reward (1 happiness 1 culture > 2 culture IMO) but the cobra is also more rare. In summary, I think the reward for the great cobra is fine.
Progressions are not meant to be the same for all animals. They are just meant to have a similar power level than other animals of the same tier. Great cobra is tier 0, while the crocodile is tier 1. The cobra is meant to fill the previously empty niches in the desert and that was tier 0 (tier 1 and above already have stuff like lion prides, scorpions and the like).
I'm unsure if I mentioned this earlier, but I don't think that ALL high tier animals should give an special reward. In the specific case of the giant cobra, at high wilderness deserts you can already get Lion Trophies, Scorpion pens and Lizard trophies (and Crocodile trophies if there are some flood plains around) so IMO that's already quite enough rewards.
My reasoning for movement penalty is that terrain features such as forests and the like should impede the movement of huge creatures far more than it does with smaller ones. In fact they already do for animals that are far smaller than the proposed gargantuan animals, such as plain normal horses, elephants and the like. From the bestiary entry about huge animals, I picture them as slow and powerful behemots. I don't have much proof for this, but that's what I took into account for designing them.
Also, all gargantuan animals are expected to use roads. If I catch a gargantuan animal, I'm not going to waste it to create some building (I could use a normal animal for that), I'd use it for war.
While writing this post I understood that you meant that the normal boar gets only one move while the gargantuan one gets two. This is an overlook on my part; I never meant to give them different speeds. I don't remember if I meant to give them 1 speed or 2; probably 1 as the normal boar is stronger than other animals of their tier already.
Great cobra's reward is somewhat better than the wolf pen's reward (1 happiness 1 culture > 2 culture IMO) but the cobra is also more rare. In summary, I think the reward for the great cobra is fine.
Progressions are not meant to be the same for all animals. They are just meant to have a similar power level than other animals of the same tier. Great cobra is tier 0, while the crocodile is tier 1. The cobra is meant to fill the previously empty niches in the desert and that was tier 0 (tier 1 and above already have stuff like lion prides, scorpions and the like).
I'm unsure if I mentioned this earlier, but I don't think that ALL high tier animals should give an special reward. In the specific case of the giant cobra, at high wilderness deserts you can already get Lion Trophies, Scorpion pens and Lizard trophies (and Crocodile trophies if there are some flood plains around) so IMO that's already quite enough rewards.
My reasoning for movement penalty is that terrain features such as forests and the like should impede the movement of huge creatures far more than it does with smaller ones. In fact they already do for animals that are far smaller than the proposed gargantuan animals, such as plain normal horses, elephants and the like. From the bestiary entry about huge animals, I picture them as slow and powerful behemots. I don't have much proof for this, but that's what I took into account for designing them.
Also, all gargantuan animals are expected to use roads. If I catch a gargantuan animal, I'm not going to waste it to create some building (I could use a normal animal for that), I'd use it for war.
While writing this post I understood that you meant that the normal boar gets only one move while the gargantuan one gets two. This is an overlook on my part; I never meant to give them different speeds. I don't remember if I meant to give them 1 speed or 2; probably 1 as the normal boar is stronger than other animals of their tier already.
