I'd like to request a few changes:
1. Make the "adjusted calculated replaygain values" slider larger. It's difficult to slide in 0.1dB increments. An alternative would be to put inc/dec buttons on either side to bump the adjustment up/down by 0.1dB.
2. Add a Zero button to the "adjusted calculated replaygain values" slider. That makes it easier to reset the dialog from the last album it processed.
3. Don't auto-dismiss the dialog. Or add an option to auto-dismiss. I've found that occasionally, when I need to adjust several tracks' track-specific replay gain settings, sometimes the dialog will auto-dismiss even though a few of the tracks actually would clip (even with the alert checked on).
4. Would it be so difficult to add some logic to this whole process to fully automate the replay gain values to prevent clipping for both tracks and album values? As it stands now, I typically start with both basis checked and 0dB, then (if necessary) I have to manually adjust the album basis first, then go through each track (that clips) individually adjusting them. Seems like this could be totally automated.