Yes believe me – I get the frustration if you’re assuming it’s one UI to rule them all 
I think you’re still assuming this is mostly a “front end” change. It simply isn’t. The old UI is the source of numerous stability and performance issues. Plus, it definitely couldn’t support the level of styling and customization that we already have in the new UI.
Yes we are asking the experienced creators to put in some effort to change the UI and suit their needs. In our many months of testing, it doesn’t seem to take long for folks to make their adjustments and it certainly isn’t an ongoing thing. In fact, another nice thing about customization is we can’t disrupt your preferences quite as easily.
You are right - the Import button was my example. You are welcome to have Undo and Redo buttons on every single tab. You can right click on any tab we provide, duplicate it, hide the original, and customize the copy. Not only can you add Undo/Redo, you can kill anything you don’t use, and add any plugins you want to that same tab.
If you want to get really crazy with customization, you can dig into the JSON (wow that post is almost a year old… we are hoping to update these docs a bit more). You can also share custom tab files with others.
And seriously: thanks again for sharing your impressions and giving us a chance to explain with some detail.