Of all the proposed improvements, the Replay Gain Task is the only one that has the potential to actually improve the quality of the actual audio.
I have discovered that the algorithms used to calculate and set the replay gain can inadvertently increase the levels too high and cause brief audible clipping upon playback of loud passages. These potentially offending replay gains are always positive numbers, so a task that could locate a range of replay gain values and replace them automatically could be very helpful. Ideally, you could choose a specific dB reduction from the calculated value or specify a specific value, such as 0dB.
Until I discovered this, I was forced to not use the replay gain feature of my players, but after adjusting the offending values, I now use the replay gain feature with no loss of fidelity. My preferred player is Audirvana, which currently does not have the ability to adjust the replay gain from within the application.
I currently have added replay gain as a primary field in SongKong, and use that method to correct problem recordings. So THANK YOU for including Replay Gain as an editable field! It has made a great improvement to the quality my overall audio experience!