I installed R25 on my work machine and I honestly love the interface changes, even though Maxon has not only taken a lesson out of Blender's book, but also from other programs, it seems.. 😉
I don't find the new UI particularly hard to get used to. Watch Chris Schmidt's interface part on the new R25 features and you'll get accustomed to it in no time. There's also a knowledge base article at Maxon's website detailing the changes. The additional viewport real estate is great and the changed locations of the toolbars make absolute sense. I know nobody asked for it, as Cinema has always had a great UI, but the changes are very well thought out and make a great UI even better. If you have access to R25, give it a try.
Now for the rest, I am also underwhelmed, albeit not as much as others here. I love procedural and node workflows, so getting even an interim solution for incorporating scene nodes into the Object manager is exciting for me. That said, I agree that it's debatable to tout this as a full feature, as nobody knows how the system will change and / or evolve until the core and the scene nodes are finished.
For spline import, I do not care much. The tracker tag seems a nice addition for animators with some very smart and easy to use parameters, but I don't animate.
Overall, I wouldn't say I am disappointed nor particularly impressed by this release. It's really lightweight and there is not enough incentive in the feature list for me to upgrade my personal perpetual R23 license, also considering the perpetual upgrading cost. But I enjoy having access to the new interface and capsules on my work machine and appreciate the changes that are there, because they are done well. And Cinema is still the general purpose DCC app I can learn the easiest and that I enjoy working with the most.
Also, I understand the community's frustration and that the patience of waiting for the new core to see all of the outdated areas addressed has been wearing thin by now. Where I disagree is that Maxon does not know where to go with the roadmap. I am sure they have a long-term plan, or else they would not invest so much into the scene nodes approach. Whether this is going after Houdini, enabling completely new features that are done more intuitively than anywhere once they finally land in C4D or it's something completely different, I don't know. It's pure speculation. But I find it a bit naive to think that development was "random". A company of Maxon's size, not even talking about Nemetschek here, certainly has an intent with everything they develop. Whether or not this intent will align with the customer's wishes remains to be seen, but I am sure there is some intent in planning.