I disagree. Recently, I formatted my macbook pro and decided maybe I don't need all these "new features" in Sierra and would be fine with Mavericks.
Turned out it is more complicated than that.
- The external screen renders better under Sierra than Mavericks. I didn't notice the change since it happened gradually and I don't know which version triggered it. But it was annoying enough to notice.
- The battery life under Sierra is much better. I noticed a 10-20% extended lifetime.
- Some apps would not work.
- I missed the Sync between my iDevices. I didn't know that it didn't exist in Mavericks.
- Finder is more responsive in Sierra than Mavericks
I really came to appreciate Sierra after that reset to Mavericks. In fact, I couldn't work with it and decided to upgrade. What High Sierra brings to the table is "unnoticeable" UI wise but makes your workflow easier.
These small improvements performance wise makes your work easier and better. On the longterm they accumulate and are making macOs still the best OS I have ever interacted with.
Mavericks is 4 versions old (10.9), Sierra is current version (10.12), High Sierra is the on that adds these features you're talking about (10.13). In between were Yosemite and El Capitan.