The current Shield particle is a bubble. While the bubble is a perfect design, there are more emaesthetic features that it could possess.
Alteration 1: Cracks.
Whenever hit, instead of turning a different color, the Shield bubble would gain a "cracked" look that increased with every increment of damage it took. For example, instead of changing color, a crack would appear/lengthen at a fixed point on the Shield bubble. Turning while shielded would cause the cracks to move as well.
As the shield regenerated, the cracks would steadily disappear, essentially lengthening in reverse.
A cracked shield would steadily increase in transparency, until the cracks were more visible than the rest of the bubble. Then, it would shatter, playing an animation of the shield bubble breaking apart like chunks of glass.
A shield regenerating from being shattered would play the "shatter" animation in reverse, with the shield appearing to repair itself.
Addition 2: Coloration.
Instead of going from Blue to Red, a shield bubble should be Prismatic, becoming like the Guardian lockdown shields in terms of visual durability.
Crack effects on the shield bubble would be the color of the shield's resistance type, with any damage type overriding Normal for coloration. This damage resist color would also be the color of the broken shield bubble.
Addition 3: Pulsing Energy.
A fully functional Shield Bubble would give off a wide, visually soft, Prismatic ring of energy that would begin at the front of the bubble, stretch to encompass the bubble's midsection, then shrink again as it reached the back. Pulses would become more frequent and thinner as the shield became damaged, with a broken shield emitting no pulse until it starts to regenerate, in which case the pulses would be line-thin and become more frequent as the shield began to repair. (Think respawn pads)
This is an addition to my loosely-related Charge Differentiation post.
Thoughts?
Cracks is interesting, but the colored shield feedback is a valuable asset to assessing how strong your and teammate shields are. I would say have cracks be colored as well.
Coloration is a bit flawed due to multiple specialized damage typed shields existing. Having swirling colors for its damage type would be alright. However, the "shield wobble" is a bit harder to work with. Perhaps a shield wobble + slowly becoming a transparent bubble?
Pulse is interesting. Perhaps the pulse would change color too? Or would the normal shield bubble simply give off a prismatic pulse on top of it? The latter would probably be better.