Looking at my answer above I see that I should have put this in a more polite way, sorry for the harsh tone. I should back up my critique with screenshots and examples but I'm not going to be in front of my PC for the next 1-2 weeks and just can't be more specific right now. Not ideal, but I hope it's clear why the current approach isn't very user friendly right now.
What I dislike is that without inspecting maps or map trees you won't be able to tell what the IOR value is. Also, by using values outside of 0-1 map thumbnails will always be white, making it impossible to quickly check the final map, especially if you stack them you want to know what you're doing - an all white final map result won't tell you anything.
By mapping the map/map tree values instead you can immediately see what the final map stack is, since it displays in 0-255 and you specify the max IOR value in a numerical way right within the material's UI. This way you get the info much quicker with the same result.
I'm eager to see why others don't see anything wrong in going the more winded route. Maybe I'm missing something and judge too quickly.
Sorry again, Maru.