When I first started being hit after the shields used up was a good indicator that I am close to death, thus as soon as my screen flashed red I kicked it up and 'ran' away. Now that I have 200 HP to the armor I can stay and perhaps finish off the enemy before I die.
Since I'm in battle its difficult to keep track of where my ship is pointing (to fire on the enemy) and keep track of my wingmen (so I don't accidentally lead to their deaths) and keep track of my HP left. A Tiny message at the bottom of the screen is all but lost when your wingmen are telling you good shooting or 'Hey watch your fire' (In reality they need to watch where they are flying

It would be nice if the flash of red would indicate when you are near the end of your HP, say when you are down to your last 25% of HP - thus for 100 HP you have 25 HP left on your shields, at 200 HP you have 50 Left. This way the flash of red indicates that you are going to die real soon if you don't get your stern out of there.
Along the same note.
I notice there are Red and there are Green (shades of green I am told, I'm slightly color blind thus can't tell the difference in the greens) but there are no yellow.
Green - Allied
Red - Enemy
Yellow - Neutral such as dead stations which remain red even when dead silly.
Perhaps a yellow flash when your armor is half used up - this way you have a visual cue without having to glance down at the plating hud every few seconds, Red when you are down to a quarter.