Sure so it's quite a few things actually!
1. I really like the Cars movies as a franchise. Well most of them anyway, I found it to a really enjoyable watch and I think its sad that they haven't done much with them in a while, this definitely has a chance to revitalize it a little bit atleast in the public mind.
2. I never liked the ROA all that much, atleast here in WDW. In Disneyland, it is an important part of its history. But WDW? Eh, its history but it was never as good as Disneyland's version. If something is always going to be a weaker version of the actually beloved thing, why use up like 14 acres of land in the most visited theme park in the world??
3. I've never liked TSI ever all that much. It's also suffering a similar problem with feeling like space that could be made much better. Now do I think there should be more play places in WDW? Absolutely, but I never really liked this one in particular for whatever reason. It didn't feel like a true play place to me or my family.
4. Having 3 big flashy rides in frontierland + finally an actual ride that young kids can do is great! It helps balance out the right side HEAVY park as rn we have Liberty Square with only 1 main headliner, Frontierland with 2, and Adventureland with 2. Meanwhile Tomorrowland atleast has 3 and Fantasyland has a TON. The park needs more balance and my suspicions were confirmed when I went to WDW and the whole left hand side of the park had walkons (except Tiana's) for the first hour or two while the other side of the park was terrible in waiting. While this was good for me, it meant that my day quickly slowed down once hitting the brick wall that is the right side of the park while the left side almost went "too fast"
5. This helps gives access to the Villians land section and seems to allow multiple entrances to reduce bottlenecking and create a decent flow of guests in this side of the park. There's 2 other MK attractions I would remove to also help this but thats neither here nor there