Well strictly speaking, the returns under the current design are unchanging: each pull has the same odds as the previous. The expected marginal rate of output is the same per gem invested. There is not a diminishing rate of return, only a flat rate. Your design was suggesting that there be an increasing rate of return, which is something that others, including myself, have suggested.
(I’m a professional economist, FWIW, so this is lingo that we share.)
I definitely would like to see a little less randomness in the game. Today you get tokens randomly to make random pulls of heroes that you need random-drop ascension mats to progress to play in a randomly generated board.