To reverse and accidental bookmark, go to System Preferences > Keyboard > Shortcuts and turn on Full Keyboard Access for "All controls". Now one can use the tab key to highlight the Remove button then hit return to reverse.
Use xe2x8cx98+L to highlight the URL thus taking you to the Address bar.
From Chrome Support:
xe2x8cx98+L Highlights the URL.
Takes a bit of retraining of muscle memory, but this is faster and is less complicated than trying to remap the Bookmark shortcut, which is built in by Google.
NOTE: This works in Safari and several other browsers too.