I definetly agree with the idea of making game visuals more intuitive, as long as it doesn't affect balance.
Just out of my head I see 2 possible effects your way of changing the shield bubble could have.
Overspill: if I remember correctly how overspill works, and understand your idea correctly, the resulting shield would be smaller, therefore also reducing the area other shieldbats would take overspill damage in. This might be an issue due to the stranght of shieldboats.
Interactions with air. From how I understand your idea, you move the centr of the shield upwards while reducing the shield radius. This might move the top of the shield higher (or lower the the reduction in the sheld radius is sufficiently large), which can change the interactions of shieldboats with air, making it easier/more difficicult to move an airunit inside the shield bubble to snipe the shieldboat.
Therefore such a change might need some testing and adjustments.