That's true the twist-grip range of motion has stayed constant so it's not a perfect analogy, but as you admit your map does require significantly more twist grip action to achieve the same throttle position (for the most part), like going to a slower turn throttle would do. I'm not saying that's a bad thing I'm just not convinced it's a good thing.
I have never heard anyone argue that they want to have to turn their throttle twice as far to get the same throttle opening. You tout that as a benefit but personally I have no issues with throttle modulation off bottom. I want my throttle more linear. If someone does have that issue though then they will probably like your tune.
I also fly model helicopters and airplanes, and in that hobby a lot of people use substantial amounts of expo (exponential) when setting their pitch and roll curves, to reduce sensitivity near mid-stick. For example I used to fly at a field with a bunch of old guys. One of the guys let me fly his tiny model F-22 that he was having trouble with. I flew it and hated it because he had the expo turned up so high that I had to move the stick really far to get it to do what I wanted. I turned the expo down and then it flew really nice. The old guy tried it with my setup and he hated it, was twitching all over the place.
So my point is that some people like a lot of expo, some like a little. I personally use very little to no expo because I like having a very responsive vehicle. No right or wrong answer though it's just preference.
That is why I keep asking for your subjective opinion, we can look at graphs all day long but all that matters is how it feels to ride, after 30 iterations, does it feel good? Have you tried the Euro map back to back?
About your last plot that is not what I am saying at all