I honestly don't understand your reasoning here. What does it matter if 2 is small compared to 20, while 35 is relatively large? It makes no sense to say that the result of 1d20+35 is determined more by the modifier than fate. While I agree that a larger fraction of the sum stems from the modifier than from the die roll, I fail to see the relevance in this. To me, you could just as well include the colour of the d20 in the argument as well.It absolutely is relative, but let me be clear what "it" I'm talking about. While you are correct that the odds are exactly the same (second consideration), the result of 1d20+35 is determined more by the character (modifier) than fate (1d20), while the result of 1d20+2 is determined mostly by fate. That they have exactly the same chance of producing success (for target numbers 50 and 17, respectively) is irrelevant to the first consideration (2 is small compared to 20, while 35 is relatively large).
I could see that if could be significant if we measured how may times higher than the target number we rolled. Then fate would start to mean less and less the more the numbers rose. But that is not the case here. The result taken in isolation is just a number. No part of the equation 1d20+35 can take more or less credit for arriving at exactly that number.