Modding large shields have been a problem since ever and the larger the more lag it causes especially trying to create a large wall shield. At a certain radius size the shield would be capped and disappear. We have been addressing and discussing this multiple times and for a long time. So I would like to amend and combine this effort with my suggestions about custom hitboxes from last summer:
Creating a single hit-line that can be dual-used as shield and hit box. It would be setup using a distance (length) and a width for size. It would be preferable if they can be dynamically resized using buffs. The line does need a shield specific component for rendering and hiteffects.