Somebody actually kills all the Reivers in Locus Requiescat? I always thought the intent of the excessive mob spawning in hexdd was to essentially time limit the maps. In that sense, also in the sense of a speedrunner, this mod is good. I can see vanilla Mage being better in some situations for a completionist run, however.
As for the mod itself, I suggest moving the brightmaps to a separate pk3 file. I don't think gzdoom has a toggle for brightmaps, and I don't play with them.