All bomber armors are elemental, except for that kat cowl.
A shield would let us equip at least one piece of pierce/shadow defense withotut resorting to UVs or trinkets.

UVs are the bonus effects which equipment may gain on top of its natural effects. Natural bonuses are things like +bomb damage on Bombastic, +beast on Drake to Dragon line, and -universal attack speed for the two Plate lines and Ancient if you discount that as part of the family. It was adopted.

The three shields that give natural bonuses are Scarlet (+2 max health), the Snarbolax shield (+1 sword damage from 2* to 4*, +2 sword damage at 5*) and Swiftstike (+3 universal attack speed). The only weapon specific one of these three is the Snarbolax shield. Bombs gain the least from attack speed with Swiftstrike. Scarlet is under the mountain of health trinkets.

One of the benefits for bombers when it comes to equipment (I should say used to be benefits) is Mad Bomber which has substantial weapon bonuses in exchange for any form of status resistance, lower normal defense than the average 5* armor, and even weakness to four common statuses. Chaos was allegedly buffed to create a "glass cannon" set and Mad Bomber was likely forgotten because Nick and friends hate bombers or their hate was strong enough to take one of the few things bombers had over the other two weapon types and completely outclass it. Painful incompetence or hateful belittling, pick your poison. I would rather have the chicken.

Shield effects are all part of the active ability when you use your shield excluding bonuses of the three previously mentioned shields which contribute outside what the shield itself does when you activate it. Swiftstrike is balanced as its bonus is weighed against its defense, though as a 3* shield being used in T2 it works well for defense. In T3 it becomes riskier because everything hits significantly harder but you get +3 attack speed for all weapons, any race and age; but it breaks easily. Avoid being hit. No penalty. The Snarbolax shield has great defenses and a huge sword damage bonus. If Nick and friends were competent in balancing this game it would have lost at least a couple bars of defense months ago. Scarlet is usable but not viable since its bonus effect only helps if you decide to take the hit instead of having the shield tank for you.

There are a lot of completely original effects that could be put on shields that work similar to those three shields. A shield with only some element and shock defense but gives a big chunk of movement speed while charging a bomb. A shield that can bump your bomb a short distance if you shield next to it. A shield that can pick up your bomb, pause its fuse, and let you place the bomb again but making you unable to charge another bomb while carrying a previously charged one. These are a couple things that people have asked for at least a couple times.