That’s what you see in Windows 8.1 Update. There are no major changes, and precious few minor ones that extend beyond default changes and a few dubious new capabilities -- Metro icons on the taskbar being a good example.
If you aren’t yet part of the Windows 8 generation, there’s nothing in the Update that will convince you to join the Jekyll and Hyde revolution.
If you’re running Windows 8 or 8.1, yes, the Update is worth installing.
Let’s see if Microsoft can do better under new management, and with more time. Hope still springs eternal for Windows 9.