LLP is indeed quite useful. The imps have quite decent stats also. Dom 2 has some issues with the low maximum unit number but in Dom 3 those issues will hopefully be gone.
If in Dom 3 FotA is still as it is imagine massproducing LL Protections
. 10 Blood for a LL Protection
. If you use it on something stealthy you can thus avoid flames from the sky and the like.
If you would theoretically manage to build 100 LL protections e.g. i can imagine little that works well vs. it.
Optimally would be as SC pointed out be Jotun Scouts as carriers
. They wouldn't die so easily vs. Wrathful skies and similiar stuff. And 200 (or 400 with quickness) Imps a turn should kill a lot
.