I agree the loss of the Boneyard is a bit sad, I would have liked to see a new playstructure or heck even implement another archaeology dig nearby Indiana Jones.
ITTBAB was a scarier show for kids that wasn't all that well liked. While I don't think Zootopia is a great replacement overall because I think Zootopia doesn't lend itself to a show as well as something like a ride, it makes enough sense to replace. If it was up to me I would replace the show as well but add in a Bug's Life Land to flesh out Animal Kingdom with a ton more flatrides + a high quality Bugs Life dark ride but that's just me.
As cool as Excavator coaster would be, it's not necessarily a great business decision due to its somewhat similarity to BTM, lack of IP, and imo somewhat lack of a wow factor. There's moments in a lot of the new Disney ride that like to build up to a particular "wow" moment or be hyper themed. Excavator doesn't have that imo since you're going through an old dig site + dino bones.
Great to hear theres expansion space
the problem is getting people over to it was its currently blocked by stuff like Kali. I think they just want to focus right now in making the current stuff the best version it can be then working on expanding the parks. Again, ideal world would give us a ton of possible areas to put in Animal Kingdom. The problem is logistics. Since I wasn't a fan of Dinoland USA, I don't mind it going down completely. I liked Dinosaur but Indiana Jones looks so much better.