I'm not complaining about the time it takes to level nymphs, but that in order to really progress you need to use Super Nymphs, just costs premium currency. I don't get where you thought this, as I opened with:
Even then, sometimes when I go back to the game, I don't receive my idle gains; it happened around twice, out of the 3~4ish times I checked yesterday, each time around 1~3h apart from each other. -- I even saved, waiting for the heart at the bottom right to disappear, before closing the tab/browser.