The park stuff, foliage, and gameplay mechanics will likely all come via free updates or expansion packs as they have been doing. There will always be creature packs in between since those likely have the highest return on investment for Frontier. I don't see potential conflict between the two. I imagine that the people working on creatures are probably different from the people working on park stuff and gameplay mechanics.
Since we get a lot for free in the updates, I think that the overall intent is for the creature packs to cover the labour cost in giving away all of the free stuff. I think that this is similar to how games like Fortnite and Warzone offer lots of stuff for free but cover the labour costs via cosmetics. This might also explain why the creature packs feel a bit overpriced to me. If you don't want them though, don't buy them.
There are a number of various subgroups within the player base all focused on different things. Some are mission driven and focus on campaign missions, unlocking things, etc. Others are more park focused and all about designing the structural layouts and buildings and paths and stuff. Others like me came here for the dinosaurs. I know that you feel differently, but for me at least, as long as this game as DLC support, I don't think that this game could ever have too many species. Obviously, I'd prefer for new species to be more unique. However, even if they were to put in something not very unique like Mapusaurus or Kritosaurus, since I'd have the funds, I'd probably still get it just to be a completionist.
There are so many different directions that they can go with creature packs, especially since Dominion introduced feathered dinosaurs and the two synapsids Dimetrodon and Lystrosaurus. There are still more feathered dinosaurs that they can add. Gigantoraptor would be a great choice, in my opinion. I'd also like to see feathered equivalents to some of the existing species that should be feathered like Gallimimus or the medium size pterosaurs. Sure, it'd mostly just be a cosmetic difference. However, Sandbox mostly is all about creating appealing visuals, and the game already has plenty of animals that are already pretty similar looking (looking at you, ornithomimosaurs). They can add more non-dinosaur terrestrial animals now that Lystrosaurus and Dimetrodon have broken that barrier. They could add back in the Secrets of Dr. Wu hybrids. Despite its massive size, Shastasaurus / Shonisaurus is still missing from the marine reptiles roster. They could expand the lagoon roster to include other marine animals like Megalodon and Leedsichthys. The possibilities are endless.
