As I heard that the new version of the game is going to be released soon so I would suggest you to add a shield indicator at one side of the screen which is going to show you how much damage has your shield taken, also how much time it needs to be repaired and last but not least if you roll over you will see this pannel you always see when rolling over an item in your inventory.
pics:
1: http://www.flickr.com/photos/jrizos2812/8549683082/in/photostream/
2: http://www.flickr.com/photos/jrizos2812/8549683752/in/photostream/
I hope you like my idea.
PS: I made this on windows XP drawing so it's low quality the Game Masters can make this better than me.
Also, isn't the how much dmg thing already there via colour indicator?>
Charge time, maybe.