I think one very important change needs to be done to upgrades; We all know that then people click "Choose an upgrade" button and swap item with another one, the result of the current value will be saved so people may put the the previous item back in place and get the upgrade going. My suggestion is that the indicator of an upgrade should not save recent value but it should save a current maximum value for the particular item; because, I believe people have wasted enuff gold by over clicking "Choose an upgrade" button and skipping good results by accident, and the reason why they do this kind of mistake is not only because people click too fast but also because good upgrades are very rare and the process of an upgrade is very monotonous and boring. Thank you for your attention.

Definitely agree with you. It should freeze for 2 seconds when it's on red, so people will not skip a good upgrade which is so hard to get.