I don't see why the shield render would be any different. Just apply the same kind of shield hit you have on a fighter, but on the local part of the Lucifer instead ?
Rendering or collision detection aren't the issue here; FS2 already had all the necessary tools in place to make this reasonably performant. For that matter, FS1 had those mechanisms in play as well; What I am guessing is that :V: wanted to avoid a situation where players would duck under the shields and bypass them completely.
"We developed a brand new type of weapon, the GTX-Santa. It temporarily disables the shields of your target within a range of 150 meters, for 30 seconds. Use it just before bombing the Lucifer, on the part that you want to bomb."
That's something the engine actually couldn't do without some major reworking of how shields work internally. We could do such a thing now, I think, given that we have support for more than 4 shield section in place, but back in FS2? No way. Not without engineering cost which :V: was obviously unwilling to pay, given the time constraints they were under.
You'll find that most of the time, such things "begging" for an explanation in games, are 99% due to technical limitations. Regarding the shield, you should be aware that the shield mechanic in fighters means that another mesh is applied to the ship, which only renders some vague vertex to vertex shader when your lazors hit it. The problem I could see with doing this with the Lucifer is how it's just too big, which means that its shields' mesh would also be too big, and not only would it become ugly as ****, it would also probably create a huge confusion in the collision code.
There is also that. The shields on fighters look "right", but given how primitive the shield effect code was, achieving similar results on something the size and shape of the lucifer would involve creating a fairly hi-poly shield mesh, which carried a lot of cost back then (I'd guess that a Luci shield mesh would have more polygons than the retail Luci herself)
